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Improving the Performance of PVDF/PVDF-g-PEGMA Ultrafiltration Membranes by Partial Solvent Substitution with Green Solvent Dimethyl Sulfoxide during Fabrication
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  • Qidong Wu
    Qidong Wu
    College of Architecture and Environment, Institute of New Energy and Low-Carbon Technology, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610207, P. R. China
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  • Alberto Tiraferri
    Alberto Tiraferri
    Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
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    Orcidhttp://orcid.org/0000-0001-9859-1328
  • Haibo Wu
    Haibo Wu
    College of Architecture and Environment, Institute of New Energy and Low-Carbon Technology, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610207, P. R. China
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  • Wancen Xie
    Wancen Xie
    College of Architecture and Environment, Institute of New Energy and Low-Carbon Technology, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610207, P. R. China
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  • Baicang Liu*
    Baicang Liu
    College of Architecture and Environment, Institute of New Energy and Low-Carbon Technology, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610207, P. R. China
    *E-mail: [email protected], [email protected]. Tel: +86-28-85995998. Fax: +86-28-62138325.
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    Orcidhttp://orcid.org/0000-0003-3219-1924
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Cite this: ACS Omega 2019, 4, 22, 19799–19807
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https://doi.org/10.1021/acsomega.9b02674
Published November 7, 2019

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Abstract

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Traditional organic solvents used in membrane manufacturing, such as dimethylformamide and tetrahydrofuran, are generally very hazardous and harmful to the environment and human health. Their total or partial substitution with green solvent dimethyl sulfoxide (DMSO) is proposed to fabricate membranes composed of poly(vinylidene fluoride) (PVDF) blended with PVDF-graft-poly(ethylene glycol) methyl ether methacrylate (PEGMA), with the purpose to accomplish a greener chemical process and enhance the membrane performance. Various organic solvent compositions were first investigated using the Hansen solubility theory, and the best mixture was thus applied experimentally. The membrane prepared by a ratio of N,N-dimethylacetamide/DMSO = 7:3 outperformed the membranes prepared by other solvent mixtures. This membrane showed high wetting behavior with the water contact angle declining from 71 to 7° in 18 s and a pure water flux reaching values larger than 700 L m–2 h–1 under 0.07 MPa applied hydraulic pressure. The membrane rejected sodium alginate at a rate of 87%, and nearly complete flux recovery was achieved following fouling and physical cleaning. The introduction of green chemistry concepts to PVDF/PVDF-g-PEGMA blended membranes is a step forward in the goal to increase the sustainability of membrane production.

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1. Introduction

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Poly(vinylidene) fluoride (PVDF) is a well-established polymeric material to produce ultrafiltration (UF) and microfiltration (MF) membranes owing to its exceptional mechanical properties, chemical resistance, and thermal stability. (1−7) However, despite its many advantages, the hydrophobicity of PVDF can induce severe membrane fouling, which is a main obstacle that limits its applications. (8−12) Thanks to the compatibility of the PVDF matrix with amphiphilic copolymers, modifications of PVDF membranes by blending with other more hydrophilic components have been reported widely. (13−17) The atom transfer radical polymerization (ATRP) method can be applied to enhance the properties of polymers by grafting chains with different characteristics, making the preparation of many new copolymers possible. (18−25) Specifically, PVDF-graft-poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) has been successfully synthesized and characterized. (20,26,27) Membranes with promising fouling resistance behavior were thus produced by blending this PVDF-g-PEGMA material with traditional PVDF. (28)
Liu et al. fabricated high-performance and detect-free membranes consisting of PVDF blended with PVDF-g-PEGMA with a unique periodic nodular structure. (28) The membrane exhibited a high sodium alginate (SA) rejection and a very high water permeance of 5170 L m–2 h–1 bar–1, roughly 1 magnitude higher than that obtained by Hashim et al. or achieved by commercial membranes. (29) Chen et al. further explored the formation mechanism of the periodic nodular structure, and they found that the structure can only be obtained when PVDF-g-PEGMA and 1-methyl-2-pyrrolidinone (NMP) are deployed in the casting solution. (30) Wang et al. investigated the properties of membranes fabricated using PVDF-g-PEGMA obtained by different synthesis reaction times and found that the membrane pore size distribution of the final membrane is a function of this parameter. (31) Wang et al. also incorporated nonwoven poly(ethylene terephthalate) (PET) fabrics as a support layer to enhance the mechanical properties of the fabricated PVDF blended PVDF-g-PEGMA ultrafiltration membrane and to increase the resistance to a pressure up to 23.3 MPa, thus satisfying the requirements for industrial applications. (8)
Previous studies were mainly focused on the performance of the blended PVDF-based membranes. There, and in the vast majority of the membrane fabrication studies, the hazards intrinsic in the use of the traditional solvent have been neglected. Traditional organic solvents are toxic and hazardous. For example, dimethylformamide (DMF), a flammable liquid, is dangerous if inhaled or exposed to skin and may cause fertility problems. The concepts of green chemistry have been proposed for some time and have developed rapidly. (32−34) The objectives of green chemistry are to decrease the production and use of hazardous substances and reduce the energy consumption, moving toward renewable sources. (32,34,35) Anastas and Werner proposed 12 principles of green chemistry (36) with the main goal to prevent contaminations at the very beginning of the production stage. (32,33) In the membrane manufacturing process, solvents play a critical part in determining the properties of the membrane by influencing the solvent–nonsolvent and solvent–polymer interactions. Switching toward greener solvents while maintaining or improving the membrane performance is far from a trivial task. (34,37−39) Nevertheless, green solvents should be used for membrane fabrication to reduce the impact and to facilitate the operation of this industrial process, especially considering that the ultimate goal of many membrane applications is precisely the removal of contaminations from liquid streams. (40,41) Solvent dimethyl sulfoxide (DMSO) is a green solvent that is nontoxic and more easily recyclable compared to traditional solvents. (42−44)
Based on the concept of green chemistry and on our previous studies on PVDF-based membranes, we optimize the fabrication of membranes composed of PVDF blended with PVDF-g-PEGMA by substituting traditional solvents, e.g., tetrahydrofuran (THF), DMF, and NMP, with DMSO. The optimal partial substitution is estimated using the Hansen solubility theory to investigate quantitatively the polymer–solvent interaction and to ensure the compatibility between solvents and polymers. (45) We thus fabricate membranes using the promising solvent mixtures, and we evaluate the performance and the characteristics of the membranes under ultrafiltration conditions. The goal of this study is to fabricate a membrane with desired structural properties and high performance in terms of both productivity and removal of organic macromolecules using a greener synthesis route.

2. Materials and Methods

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2.1. Chemicals and Materials

PVDF (average Mw = 534 K), PEGMA (Mn = 500 g mol–1), 4-4′-dimethyl-2-2′-dipyridyl (DMDP, 99.5%), NMP (anhydrous, 99.5%), silicone oil, DMF (99.8%), DMSO (99.9%), THF (≥99.9%), copper(I) chloride (CuCl, trace metals basis, ≥99.995%), N,N-dimethylacetamide (DMAc, Reagent Plus, 99%), NaCl (ACS reagent, ≥99.0%), and sodium alginate (SA, Halal grade) were purchased from MilliporeSigma (St. Louis, Missouri). Deionized water (DI water) was produced using an ultrapure water system purchased from Ulupure (Chengdu, China).

2.2. Procedure to Synthesize the Graft Copolymer PVDF-g-PEGMA

The procedure to synthesize the PVDF-g-PEGMA copolymer was conducted as follows: (28,31) 5 g of PVDF was dissolved in 40 mL of NMP at 50 °C in a conical flask while stirring. Then, 50 mL of PEGMA, 0.23 g of DMDP, and 0.04 g of CuCl were added to the same conical flask, which had already been cooled to room temperature. Right after this addition, the reaction mixture was stirred at 200 rpm and bubbled using nitrogen gas for 30 min. The flask was sealed using a rubber septum to prevent air oxygen from disturbing the ATRP. (24) Then, a silicon oil bath was used to heat the conical flask to 90 °C. The high-temperature reaction lasted for 19 h with stirring. Finally, the resulting copolymer mixture was sealed and stored at room temperature. (31)

2.3. Calculation of the Hanson Solubility Parameter

According to the Hansen solubility theory, the affinity between the solvent and polymer can be analyzed quantitatively. δt, the total solubility parameter, is the combination of three parameters: δd, δh, and δp, which quantitatively represent the dispersion parameter (δd), the hydrogen bonding parameter (δh), and the polar parameter (δp), respectively. δd, δh, and δp can be calculated using the following equations. (46)
(1)
(2)
(3)
(4)
where Fdi is the group contribution to the dispersion component. The parameter Ehi represents the hydrogen bonding energy for each structure group. The Fpi parameter is the group contribution to the polar force component. For mixed solvents, such as binary mixed solvents, δd, δh, and δp can be calculated using the volume fraction for each solvent by applying the following equation
(5)
Application of the mixing law allows calculation of the solubility parameters of mixed solvents as
(6)
(7)
(8)
The ternary mixed solvents can be calculated using the analogous methodology for three components. The affinity between the polymer and solvents can be represented by the value of Ra, which was calculated as follows
(9)
The detailed calculations of the solvents used in the experiments can be found in the Supporting Information (SI).

2.4. Membrane Casting

Table 1 lists the compositions of casting solutions used for membrane synthesis in this study. All of the membranes were synthesized at a constant room temperature of 25 °C and ∼45% humidity, controlled by an air conditioner. The casting solutions were added to a conical flask and then heated to 60 °C while stirring at 500 rpm. After the copolymer and PVDF powder were dissolved completely, the solution was degassed for at least 2 h before casting. Next, the solution was cast using an 8 in.-wide doctor blade (Universal blade applicator, Paul N. Gardner Company, Inc., Pompano Beach, FL) on a first-grade surface optical glass; the gate height of the blade was set to be 200 μm. Then, the glass was immersed in a bath that contained deionized water at room temperature (25 °C). After 48 h, some of the cast membranes were air-dried for 24 h for further investigation and the others were kept in DI water at 4 °C for further experiments.
Table 1. Compositions and Viscosities of the Casting Solutions
membrane IDPVDF (g)DMAc (g)DMSO (g)NMP (g)THF (g)DMF (g)PVDF-g-PEGMA (g)PVDF-g-PEGMA/PVDF (w/w %)viscosity (mPa·s, 25 °C)
PVDF1-DMSO12.0 86.2   1.815834
PVDF2-DMAc and DMSOa12.060.325.9   1.815595
PVDF3-DMSO and NMPb12.0 43.143.1  1.815775
PVDF4-DMSO, THF, and DMFc12.0 43.1 12.930.21.815523
a

The casting solution of PVDF2 contains 70% DMAc and 30% DMSO.

b

The casting solution of PVDF3 contains 50% DMSO and 50% NMP.

c

The casting solution of PVDF4 contains 50% DMSO, 15% THF, and 35% DMF.

2.5. Model Foulant

The antifouling performance of the membranes was evaluated using a model extracellular polymeric substance, namely, sodium alginate (SA). The SA stock solution of 2 g L–1 was prepared in deionized water and stored at 4 °C. In this experiment, the UV–vis spectrometer (Thermo Orion Aquamate 8000) was used to determine the concentrations of SA with a fixed wavelength of 220 nm. (47,48)

2.6. Membrane Characterizations

The elemental surface composition of the membrane for a depth within 5 nm was analyzed using X-ray photoelectron spectroscopy (XPS, Axis Ultra, Kratos Analytical Ltd., U.K.). The spectra with 1 eV scan resolution were obtained by sweeping over the electron binding energy range of 0–1200 eV; then, the atomic concentrations of the corresponding elements were calculated from peak areas following high-resolution scans with 0.1 eV resolution. The spectra of Fourier transform infrared attenuated total reflectance (FTIR-ATR, Alpha, Bruker) were obtained by collecting over the 650–4000 cm–1 wavenumber range with 64 scans of 2 cm–1 resolution. The membrane morphology was observed using field-emission scanning electron microscopy (FESEM, JSM-7500F, JEOL Ltd., Tokyo, Japan). To observe the cross-sectional morphology, the samples were frozen using liquid nitrogen for 3 min before brittle fracture. The membrane samples were first fixed on stubs using carbon tape and then sputter-coated with a gold layer of ∼2 nm (Q150R-ES, Quorum, U.K.). The images were taken under a 5 kV accelerating voltage with different magnifications. The thickness of the membranes was measured using an electronic digital micrometer (Marathon Watch Company Ltd., Canada).
The contact angles of the blended membranes were measured using the KRÜSS DSA 25S measuring apparatus (KRÜSS GmbH, Germany). For each measurement, DI water droplets (2 μL) were placed on the sample surface to obtain the dynamic variations of the contact angle for a time period of 18 s, starting from the instant when the droplet was placed on the sample. The experiment was repeated at different locations on the membrane for about 10 spots. Atomic force microscopy (AFM, Multimode 8, Bruker, Germany) was used to obtain the surface roughness. In this test, a resonant frequency of 0.997 kHz was used to scan the membranes on 5 μm × 5 μm size areas at least 2 times. The viscosity of the casting solutions was measured by a rotary viscometer (NDJ-79, Changji Geological Instrument Co. Ltd., Shanghai) using 10 mL casting solution samples at 25 °C. The mechanical properties of the fabricated membranes were measured by an electronic single fiber strength meter (Yuanmao Instrument Co. Ltd., Laizhou, China). This experiment was repeated at least 10 times using samples with a length of 10 mm and an operational speed of 10 mm min–1. The maximum and minimum values of the tensile strength were discarded, and the average value was then calculated. The detailed mechanical performance of the fabricated membranes can be found in the SI.
A dead-end filtration cell (Amicon 8200, Millipore) was used to measure the permeability and the antifouling performance of the membranes. The membranes were cut into circular samples with an effective area of 28.7 cm2. The filtration cell (200 mL) was connected to a dispensing vessel (5 L). The permeate stream was recorded every minute. All of the experiments were performed at room temperature, and nitrogen gas was used to maintain a constant pressure of 0.07 MPa (10 psi). For each pure water filtration or antifouling experiment, the duration of the flux measurement was the lesser one between a predetermined time or the time needed to filter 4 L of feed water. First, the membrane sample was compacted using 4 L of water for 2 h, while the flux of permeate water was recorded as Jw1 (L m–2 h–1). Second, a conditioning period of the membrane followed using 4 L of NaCl solution of 10 mM L–1 as a feed for 2 h. Third, the model fouling test was conducted using 4 L of feed solution that contained 20 mg L–1 SA and 10 mmol L–1 NaCl for 5 h. During the fouling test, the concentration polarization was minimized using a stirring plate (PC-420D, Corning) adjusted to 200 rpm, on which the filtration cell was placed. The flux was recorded as Jp (L m–2 h–1). Finally, the membrane was physically cleaned using a constant DI water flow of 2.7 L min–1 for 1 min, maintaining the water surface 25 cm above the membrane surface. After cleaning, the recovery flux, Jw2 (L m–2 h–1), was measured using water as feed solution for 1 h. The flux recovery ratio (FRR), total flux decline ratio (DRt), reversible flux decline ratio (DRr), and irreversible flux decline ratio (DRir) were calculated by the following equations using an average value from three tests. (18,49,50)
(10)
(11)
(12)
(13)

3. Results and Discussion

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3.1. Elemental Composition of the Membranes

XPS results of all of the PVDF/PVDF-g-PEGMA membranes are displayed in Figure 1. The membrane was synthesized using a PVDF/PVDF-g-PEGMA mixture dissolved in different organic solvents or solvent mixtures. The composition percentage of the three main elements was within a small range, with oxygen ∼12.6%, carbon ∼61.4%, and fluorine ∼25.5%. Because the organic solvents and the unreacted PEGMA diffused out from the polymer film and into water during phase separation, the only source of oxygen in the samples was the PEGMA segments in the PVDF-g-PEGMA chains. The appearance of oxygen in the spectra, besides carbon and fluorine, reflects that the amphiphilic PEGMA segments in the PVDF-g-PEGMA migrated preferentially to the membrane surface, indicating the successful blending of PVDF-g-PEGMA with PVDF in different casting solutions. (31) As listed in Table 2, compared with other membranes cast previously from PVDF blended with PVDF-g-PEGMA, the content of carbon and oxygen was higher, while that of fluorine was lower. (8,28,30,31) This observation is explained with the smaller proportion of PVDF in the blend and the larger amount of PEGMA segments that migrated to the membrane surface. The viscosity might be an important factor affecting the migration of PEGMA segments to the membrane surface in this study. (31) A lower viscosity weakened the exchange barrier between the nonsolvent and solvent, which accelerated the phase inversion. Therefore, the migration of PEGMA segments to the membrane surface could be more effective. The existence of more PEGMA segments may improve some properties of the membranes. For example, it may decrease the surface tension and polarity to increase the hydrophilicity of the membrane; thus, potentially, the antifouling property of the membrane increased.

Figure 1

Figure 1. XPS spectra of the PVDF/PVDF-g-PEGMA membranes cast from different solvents or solvent mixtures: (a) PVDF1, DMSO; (b) PVDF2, DMSO/DMAc = 3:7; (c) PVDF3, DMSO/NMP = 5:5; and (d) PVDF4, DMSO/THF/DMF = 5:1.5:3.5. The content of the main elements was calculated and reported in the graphs.

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Table 2. Performance of PVDF/PVDF-g-PEGMA Fabricated in Previous Studies
membrane IDelement composition (C/O/F) (%)Davg (nm)Dmax (nm)roughness (nm)DI permeability (L m–2 h–1 bar–1)SA rejection (%)FRR (%)CA variation (deg)
JMS7 (28)a55.8/6.73/37.43118315.3517087.193973–61° (200 s)
19H (31)b52.05/12.89/35.06185930.7106873.370.873–33° (180 s)
b (30)57.72/6.37/35.9134 ± 1912627.5374873670–67° (60 s)
d (30)c56.63/6.49/36.8942 ± 2314632.7949944774–72° (60 s)
f (30)c57.83/4.67/37.515 ± 54926.3   74–73° (60 s)
M0 (8)   55.82324760 
M1 (8)d 51 ± 411819.09294482100–92° (180 s)
M2 (8)d 47 ± 39514.2800508769–20° (35 s)
a

The membranes were all fabricated using casting solution contains 18% PVDF and 15% wt PVDF-g-PEGMA. The solvent in casting solution was THF/DMF = 3:7 unless stated.

b

The solvent in casting solution was DMF.

c

The solvent in casting solution was NMP.

d

M1 and M2 had PET support layers, M1 with a thin layer of 29 nm and M2 was 84 nm.

3.2. ATR-FTIR Spectra

Figure 2 shows the ATR-FTIR spectra of PVDF/PVDF-g-PEGMA membranes. The 1727 cm–1 band represents the C═O stretching band, while the 1638 cm–1 band represents the C═C stretching band. (17,30,51) The existence of C═O bonds indicates that the PEGMA segments were present in all of the membrane surfaces, while the absence of C═C implies that the unreacted PEGMA was removed during phase separation by diffusing out into the coagulation bath. This result suggests that PEGMA was successfully grafted onto PVDF because the synthesized PVDF-g-PEGMA contains only C═O bonds and no C═C bonds.

Figure 2

Figure 2. ATR-FTIR spectra of the PVDF/PVDF-g-PEGMA membranes cast using different solvents or solvent mixtures. PVDF1, DMSO; PVDF2, DMSO/DMAc = 3:7, PVDF3, DMSO/ NMP = 5:5; and PVDF4, DMSO/THF/DMF = 5:1.5:3.5. The 1727 cm−1 peak represents C═O bonds, and the 1638 cm−1 peak represents C═C bonds. Also indicated are the peaks relative to the characteristic bonds that represent the PVDF α and β crystalline phases.

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The results from ATR-FTIR measurements can also be used to confirm the crystalline phase of the membrane. The mechanical strength properties of the membranes can be influenced by its crystalline phase. (37,52) The characteristic absorption bands at 410, 531, 615, 764, 796, 855, and 976 cm–1 represent the α crystalline phase, while the β phase is identified by the bands at 442, 468, 510, and 840 cm–1. (1,52−55) As shown in Figure 2, the γ-phase characteristic peaks at 776, 812, and 833 cm–1 were not observed for the samples prepared in this study, (52,54) while all of the membranes contained α and β PVDF crystalline phases. The 765 cm–1 band of PVDF2 and PVDF3 was more obvious than that of PVDF1 and PVDF4 membranes. The formation of α and β phases may be influenced by the temperature. (54) The α phase resulting from melting crystallization can be easily obtained at any temperature, while the 840 cm–1 band is common for both β and γ phases; when the temperature of solution crystallization is under 70 °C, the polymer solidification results in the β phase rather than the γ phase. (54)

3.3. Membrane Morphology

Micrographs of surface and cross-sectional morphologies were acquired using SEM, and representative images are shown in Figure 3. Using DMSO only as a solvent resulted in a surface with large pore sizes and irregular pore distribution. Therefore, total substitution of traditional solvents with DMSO was not a successful attempt, which may lead to defects on the membrane surface. After mixing DMSO with a certain percentage of traditional solvents, the pore size significantly decreased. Table 3 lists the main structural parameters of the fabricated membranes. PVDF/PVDF-g-PEGMA membranes synthesized in previous studies had pore size parameters, Davg and Dmax, of about 34 and 126 nm when using DMF/THF as the solvent mixture and 42 and 146 nm when using NMP as the solvent (Table 2). (28,30,31) In this study, the partial substitution of NMP and DMF/THF using DMSO translated in a significant pore shrinkage such that the pores could not be observed under 10k× or 100k× magnification on the surface of PVDF3 and PVDF4 membranes. (28) Relative to the cross-sectional morphologies, a top dense layer and an asymmetric structure were observed in all of the PVDF/PVDF-g-PEGMA membranes, with underlying porous fingerlike structures (PVDF1, PVDF3, and PVDF4) or macrovoids (PVDF2). The thickness of the membranes largely decreased when compared to that of PVDF/PVDF-g-PEGMA membranes synthesized in previous studies (Table 2), which was mainly due to the lower percentage of PVDF-g-PEGMA and PVDF in the casting solution. This mechanism led to a clear decrease in the mechanical strength, which was observed while handling the samples. The cross-sectional morphologies and the pore size distribution influence pure water flux, fouling, and flux recovery performance of the membrane, (37) which are discussed below.

Figure 3

Figure 3. Representative SEM micrographs of the surface and cross-section morphologies of all of the PVDF/PVDF-g-PEGMA membranes. PVDF1, DMSO (A, B); PVDF2, DMSO/DMAc = 3:7 (C, D); PVDF3, NMP/DMSO = 5:5 (E, F); and PVDF4, THF/DMF/DMSO = 1.5:3.5:5 (G, H). The membrane surface images are shown in the top row, while the cross-sectional morphologies are shown in the bottom row.

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Table 3. Properties of the PVDF/PVDF-g-PEGMA Ultrafiltration Membranes Fabricated in This Study
membrane IDDavg (nm)Dmax (nm)thickness (μm)SA rejection (%)flux recovery (%)permeability (L m–2 h–1 bar–1)roughness (μm)tensile strength (MPa)
PVDF1111.02519.09155 ± 0.646.27 ± 4.1829.16214 ± 844.1 ± 0.41.04
PVDF246.47185.91173 ± 1.587.00 ± 2.4189.33735 ± 7457.5 ± 6.10.88
PVDF3a  190 ± 2.381.21 ± 1.9686.57460 ± 2754.7 ± 3.30.34
PVDF4a  216. ± 4.681.74 ± 3.3386.38532 ± 1651.1 ± 5.91.04
a

The pore sizes of PVDF3 and PVDF4 are very small that cannot be calculated by the SEM image.

3.4. Wettability

The wettability of the PVDF/PVDF-g-PEGMA membranes was estimated through sessile drop contact angle measurements. The results are reported in Figure 4. The initial contact angles were in the same range 65–70° as our previous study, whose results are reported in Table 2. However, the changes in the contact angle of our previous membranes were small (less than 10°) in 3 min. In contrast, for the membranes fabricated in this study, the contact angle reduction as a function of time was significant, especially for PVDF2. Specifically, the contact angles decreased from 63.8 ± 2.5 to 46.1 ± 4.9° in 18 s for PVDF1, from 70.8 ± 3.8 to 7.4 ± 1.4° for PVDF2, from 69.7 ± 3.9 to 49.9 ± 4.0° for PVDF3, and from 61.0 ± 2.5 to 45.3 ± 4.9° for PVDF4, which indicated that the wettability of PVDF/PVDF-g-PEGMA membranes was significantly enhanced. (56)

Figure 4

Figure 4. Contact angles as a function of time of PVDF/PVDF-g-PEGMA membranes using different solvents or solvent mixtures. PVDF1, DMSO; PVDF2, DMSO/DMAc = 7:3, PVDF3, DMSO/NMP = 5:5; and PVDF4, DMSO/THF/DMF = 5:1.5:3.5.

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Many factors contribute to the wettability of the membrane, including the hydrophilic segments distribution, the surface roughness, and the surface pore size. (10) It has been reported that the air bubble/water droplet contact angle can be significantly affected by the surface roughness and solid surface heterogeneity. (57−59) According to the Wenzel model, a large quantity of surface amphiphilic or hydrophilic segments and a larger surface roughness will make the surface more hydrophilic. In this study, the enhancement in wettability is mainly attributed to the migration of a larger amount of PEGMA segments to the membrane surface, as well to the membrane morphology. In particular, the cross-sectional morphology observed for PVDF2 allowed faster spreading of water on this membrane. Wettability is important and may also enhance the antifouling properties of the membranes.

3.5. Surface Roughness

Representative AFM images of the fabricated PVDF/PVDF-g-PEGMA ultrafiltration membranes can be found in the SI (Figure S1), and their root mean square (RMS) surface roughness are shown in Table 3. The absolute RMS was within 60 nm. This value is larger than that of membranes fabricated in previous studies, which was about 15–30 nm. The reason is that the migration of PVDF-g-PEGMA segments to the surface can result in a larger RMS surface roughness, which is in accordance with the results reported by Liu et al. and Wang et al. (28,31) When using DMSO alone, the RMS roughness of the membrane was slightly lower than that of membranes fabricated by mixing traditional solvents with DMSO, showing that the solvent can also influence the membrane roughness. Usually, lower roughness translates into easier membrane cleaning and better antifouling properties. (60)

3.6. Membrane Transport and Antifouling Performance

The permeate flux of PVDF/PVDF-g-PEGMA membranes was recorded under a 0.07 MPa (10 psi) constant applied pressure. Figure 5 summarizes the flux profiles, the rejection rates of sodium alginate, and the fouling indices. The pure water permeabilities for PVDF1–PVDF4 were 214 ± 8 L, 735 ± 74, 460 ± 27, and 532 ± 16 L m–2 h–1 bar–1, respectively. All of the membranes exhibited a sharp decline in flux during the filtration of an SA solution, with the flux reaching a near steady-state value of approximately 100 L m–2 h–1. After physical cleaning for 1 min using pure water, the order of recovery fluxes for the four membranes was PVDF2 > PVDF3 > PVDF4 >PVDF1, which was similar to the order of highest to lowest water permeability. The different solvent or solvent mixture used in the casting dope had clearly a significant impact on flux, with variations above 300% for the membranes. Partial DMSO substitution achieved better results, with PVDF2 performing best possibly due to its better wettability and cross-sectional structure.

Figure 5

Figure 5. Transport performance and fouling behavior of the PVDF/PVDF-g-PEGMA membranes using different solvents or solvent mixtures. PVDF1, DMSO; PVDF2, DMSO/DMAc=3:7; PVDF3, DMSO/NMP=5:5; and PVDF4, DMSO/THF/DMF=5:1.5:3.5. (A) Flux as a function of time using pure water or sodium alginate as feed solution; B) FRR, DRt, DRr, and DRir indices; and (C) SA rejection.

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SA rejection rates are reported in Figure 5C. The size of the SA particle in the experiments was in the range of 15–80 nm; thus, SA particles can easily pass through the surface pores of PVDF1, leading to a low rejection rate. PVDF2 performed best, suggesting that wettability influenced the rejection and antifouling performance more than the surface pore size. Compared with membranes fabricated previously (Table 2), using DMSO decreased the SA rejection, which however was higher than 80% for the best membranes. The FRR, DRt, DRr, and DRir values of all PVDF/PVDF-g-PEGMA membranes are summarized in Figure 5B. High DRr/DRt and FRR indices are indicative of better antifouling properties, i.e., fouling reversibility, of the fabricated membranes. (61) The order of FRR and DRr/DRt ratios was PVDF3 ∼ PVDF2 > PVDF4 ≫ PVDF1. Therefore, applying a partial substitution with green solvent DMSO produced an outstanding flux recovery rate in two cases. Despite the larger roughness of the membranes, the wettability, foulant rejection, and flux recovery ratios were beyond expectation. Therefore, we can conclude that hydrophilic segments on the surface of the membrane contribute more than the roughness to the fouling behavior of the membrane. In summary, performance of PVDF2 was outstanding, while the performance of PVDF1 was not satisfying, indicating that DMSO alone is not a good solvent for PVDF/PVDF-g-PEGMA fabrication under the tested conditions. However, using DMSO to partly substitute hazardous traditional solvents is a promising way to achieve a cleaner process as well as high-performance membranes.

4. Conclusions

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Based on the calculation using the Hanson solubility theory, the total and partial substitution of hazardous traditional solvents with green solvent DMSO were investigated for the fabrication of PVDF membranes blended with PVDF-g-PEGMA. The total and partial substitution with DMSO generally improved the wettability and the fouling performance of the ultrafiltration membranes. Specifically, the membranes fabricated via partial substitution (PVDF2, 3, 4) performed better than the membrane fabricated from polymer solution of pure DMSO (PVDF1). The best performing membrane was cast from a solution containing DMAc and DMSO. This membrane had simultaneously high permeability of above 700 L m–2 h–1 bar–1, high alginate rejection (87%), and showed remarkable antifouling performance with flux recovery rates of nearly 100%. According to the results of these experiments, the partial substitution of traditional organic solvents using green solvent DMSO to synthesize ultrafiltration membranes consisting of PVDF blended with PVDF-g-PEGMA can achieve a greener chemical process while also significantly enhancing the membrane performance.

Supporting Information

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The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsomega.9b02674.

  • Calculations and experiment results; AFM morphologies of the fabricated membranes; mechanical performances of the fabricated membranes; calculation process using a group contribution method to calculate the solubility parameter of PEGMA; δd, δh, and δp values and densities of some solvents; detailed calculation of the δd, δh, and δp values of mixed solvents; FRR, DRt, DRr; and DRir results of the fabricated membranes (PDF)

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Author Information

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  • Corresponding Author
  • Authors
    • Qidong Wu - College of Architecture and Environment, Institute of New Energy and Low-Carbon Technology, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610207, P. R. China
    • Alberto Tiraferri - Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy;  Orcidhttp://orcid.org/0000-0001-9859-1328
    • Haibo Wu - College of Architecture and Environment, Institute of New Energy and Low-Carbon Technology, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610207, P. R. China
    • Wancen Xie - College of Architecture and Environment, Institute of New Energy and Low-Carbon Technology, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610207, P. R. China
  • Notes
    The authors declare no competing financial interest.

Acknowledgments

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This work was supported by the National Natural Science Foundation of China (51678377), the State Key Laboratory of Separation Membranes and Membrane Processes (Tianjin Polytechnic University) (M2-201809), and the Fundamental Research Funds for the Central Universities. Alberto Tiraferri acknowledges the support from Politecnico di Torino. The authors thank Yi He at Analytical & Testing Center, Sichuan University for SEM measurements. The authors thank Sheng Chen and Yinghui Zhao at the College of Biomass Science and Engineering, Sichuan University for measurements of solution viscosity and membrane mechanical properties. The views and ideas expressed herein are solely those of the authors and do not represent the ideas of the funding agencies in any form.

References

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This article references 61 other publications.

  1. 1
    Buonomenna, M. G.; Lopez, L. C.; Favia, P.; d’Agostino, R.; Gordano, A.; Drioli, E. New PVDF membranes: The effect of plasma surface modification on retention in nanofiltration of aqueous solution containing organic compounds. Water Res. 2007, 41, 4309– 4316,  DOI: 10.1016/j.watres.2007.06.033
    Google Scholar
    1
    New PVDF membranes: The effect of plasma surface modification on retention in nanofiltration of aqueous solution containing organic compounds
    Buonomenna, M. G.; Lopez, L. C.; Favia, P.; d'Agostino, R.; Gordano, A.; Drioli, E.
    Water Research (2007), 41 (19), 4309-4316CODEN: WATRAG; ISSN:0043-1354. (Elsevier Ltd.)
    New nanofiltration membranes were prepd. by non-solvent-induced phase inversion from a PVDF/DMF/water system. The effect of exposure time before coagulation on the membrane characteristics (morphol., thickness, overall porosity, tensile strength) was studied. PVDF membrane prepd. at a fixed exposure time of 45 s (PF45) was further plasma surface modified (RF 13.56 MHz) (PF45psm), introducing amino groups on the membrane. The performances of PF45, PF45psm and of a com. nanofiltration membrane (N30F) were tested in the removal of 2 dyes from aq. soln., characterized by different charge and mol. wt. (congo red and methylene blue). The obsd. rejections depended more on the charge of the compd. than on their mol. wts. and results were optimized for the plasma modified membrane (PF45psm) with respect to unmodified (PF45) and com. N30F membranes. In particular, methylene blue was retained for 100% by PF45psm with a relative flux of 65% compared to 38% of rejection and 59% of relative flux obsd. for N30F.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXht1ajt7%252FJ&md5=270307e1228f5537d12cee38503e6f56
  2. 2
    Chen, Y.; Deng, Q.; Mao, J.; Nie, H.; Wu, L.; Zhou, W.; Huang, B. Controlled grafting from poly(vinylidene fluoride) microfiltration membranes via reverse atom transfer radical polymerization and antifouling properties. Polymer 2007, 48, 7604– 7613,  DOI: 10.1016/j.polymer.2007.10.043
    Google Scholar
    2
    Controlled grafting from poly(vinylidene fluoride) microfiltration membranes via reverse atom transfer radical polymerization and antifouling properties
    Chen, Yiwang; Deng, Qilan; Xiao, Jichun; Nie, Huarong; Wu, Lichuan; Zhou, Weihua; Huang, Biwu
    Polymer (2007), 48 (26), 7604-7613CODEN: POLMAG; ISSN:0032-3861. (Elsevier Ltd.)
    A reverse atom transfer radical polymn. (RATRP) with benzoyl peroxide (BPO)/CuCl/2,2-bipyridine (Bpy) was applied onto grafting of poly(Me methacrylate) (PMMA) and poly(polyethylene glycol Me ether methacrylate) (PPEGMA) from poly(vinylidene fluoride) (PVDF) microfiltration (MF) membrane surfaces, including the pore surfaces. The introduction of peroxide and hydroperoxide groups onto the PVDF membranes was achieved by UV irradn. in nitrogen, followed by air exposure. RATRP from UV pretreated hydrophobic PVDF membranes was then performed for attaching well-defined homopolymer. The chem. compn. of the modified PVDF membrane surfaces was characterized by attenuated total reflectance (ATR) FT-IR spectroscopy and XPS. The surface and cross-section morphol. of membranes were studied by SEM. The pore sizes of the pristine PVDF and the PMMA grafted PVDF membranes were measured using micro-image anal. and process software. With increase of graft concn., the pore size of the modified membranes decreased and became uniform. Kinetic studies of homogeneous (in toluene soln.) system revealed a linear increase in mol. wt. with the reaction time and narrow mol. wt. distribution, indicating that the chain growth from the membrane surface was a "controlled" or "living" grafting process. The introduction of the well-defined PMMA on the PVDF membrane gave rise to hydrophilicity. Protein adsorption and protein soln. permeation expts. revealed that the UV pretreated hydrophobic PVDF membrane subjected to surface-initiated RATRP of Me methacrylate (MMA) and polyethylene glycol Me ether methacrylate (PEGMA) exhibited good antifouling property.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsVSktbjJ&md5=beba1a4ddc92b092dce79a4a8a2f52c4
  3. 3
    Bonyadi, S.; Chung, T.-S. Highly porous and macrovoid-free PVDF hollow fiber membranes for membrane distillation by a solvent-dope solution co-extrusion approach. J. Membr. Sci. 2009, 331, 66– 74,  DOI: 10.1016/j.memsci.2009.01.014
    Google Scholar
    3
    Highly porous and macrovoid-free PVDF hollow fiber membranes for membrane distillation by a solvent-dope solution co-extrusion approach
    Bonyadi, Sina; Chung, Tai-Shung
    Journal of Membrane Science (2009), 331 (1+2), 66-74CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Highly porous and macrovoid-free PVDF hollow fiber membranes are of great interest for membrane contactor applications such as sea water desalination by membrane distn. in order to enhance the flux and long term stability of the process. For the first time in this paper, porous PVDF hollow fiber membranes with high outer surface porosity were fabricated by applying a two-phase flow consisting of a solvent and a dope soln. in the air-gap region of spinning through a non-solvent induced phase sepn. process (NIPS). In this approach, the dope soln. and the N-methylpyrrolidone (NMP) solvent were co-discharged from the middle and outer channels of a triple orifice spinneret, resp. Then, the two-phase flow went through an air-gap region and finally entered the coagulation bath. It was obsd. that the introduction of the two-phase flow greatly increased the outer surface porosity of the PVDF fibers and eliminated the formation of macrovoids in the cross-section of the fibers as well. It was also found that the energy efficiency and the flux of the fibers spun through the solvent-dope soln. co-extrusion were two to three times higher than the std. dry jet wet-spun fibers. A water vapor flux as high as 67 kg/(m2 h) at 80° was obtained through the newly spun fibers.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXivVOnt7s%253D&md5=acbd77fa666645d6eb546f5c565c2f46
  4. 4
    Boributh, S.; Chanachai, A.; Jiraratananon, R. Modification of PVDF membrane by chitosan solution for reducing protein fouling. J. Membr. Sci. 2009, 342, 97– 104,  DOI: 10.1016/j.memsci.2009.06.022
    Google Scholar
    4
    Modification of PVDF membrane by chitosan solution for reducing protein fouling
    Boributh, Somnuk; Chanachai, Ampai; Jiraratananon, Ratana
    Journal of Membrane Science (2009), 342 (1-2), 97-104CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    This work studied modification of hydrophobic membrane by chitosan soln. for the purpose of reducing protein fouling. The membrane used was flatsheet poly(vinylidene fluoride) (PVDF) of 0.22 μm pore size. The membranes were modified by 3 different methods, i.e., immersion method, flow through method and the combined flow through and surface flow method. Chitosan soln. concn. and modification time were varied. The modified membranes were then neutralized with NaOH soln. The results of SEM and Fourier transform IR spectroscopy (FTIR) study of modified membranes compared to unmodified membranes confirmed that there was chitosan coated on the membrane surfaces. The water contact angles and water fluxes decreased with increasing chitosan concn. and modification time. The result also indicated that modified membranes had higher hydrophilicity than unmodified membrane. In protein fouling expt., bovine serum albumin (BSA) was used as a protein model soln. Modified membranes exhibited good anti-fouling properties in reducing the irreversible membrane fouling. The membrane modified by a combined flow through and surface flow method showed the best anti-fouling properties compared with other methods. Protein adsorption on the modified membrane was highest at the isoelec. point (IEP) of BSA soln. and decreased as the soln. pH was far from the IEP.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXps1Cksbs%253D&md5=2f6dfaf374539d1c67e3d28e8abc5077
  5. 5
    Zheng, Z.-S.; Li, B.-B.; Duan, S.-Y.; Sun, D.; Peng, C.-K. Preparation of PVDF ultrafiltration membranes using PVA as pore surface hydrophilic modification agent with improved antifouling performance. Polym. Eng. Sci. 2019, 59, E384– E393,  DOI: 10.1002/pen.24996
    Google Scholar
    5
    Preparation of PVDF ultrafiltration membranes using PVA as pore surface hydrophilic modification agent with improved antifouling performance
    Zheng, Zhao-Shan; Li, Bing-Bing; Duan, Shi-Yuan; Sun, De; Peng, Cong-Kang
    Polymer Engineering & Science (2019), 59 (S1), E384-E393CODEN: PYESAZ; ISSN:0032-3888. (John Wiley & Sons, Inc.)
    Novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes were facilely fabricated using polyvinyl alc. (PVA) aq. soln. as the coagulation bath through phase inversion method. In the process, PVA was introduced into the pore surfaces of the PVDF membranes via the interdiffusion of the non-solvent water and the solvent. The effects of PVA content in the coagulation bath on membrane properties were systematically discussed. The results indicated that the increase of PVA content in coagulation bath resulted in the formations of the more sponge-like structures and the higher surface hydrophilicity. Smaller pore size led to lower water flux and higher bovine serum albumin rejection. Fouling resistance measurement indicated that the membranes made in PVA/water coagulation bath had higher flux recovery ratio (92.1%) than the membrane made in a pure water bath (71.0%). Furthermore, mech. property test revealed that the resulting membranes had high tensile strength and Young's modulus. In this work, we found that the morphol. and the property of the novel PVDF membranes could be detd. by the PVA content in the coagulation bath.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlemsrzM&md5=e94f12c687485a1674679ac46ac2dfa8
  6. 6
    Sun, D.; Yue, D.; Li, B.; Zheng, Z.; Meng, X. Preparation and performance of the novel PVDF ultrafiltration membranes blending with PVA modified SiO2 hydrophilic nanoparticles. Polym. Eng. Sci. 2019, 59, E412– E421,  DOI: 10.1002/pen.25002
    Google Scholar
    6
    Preparation and performance of the novel PVDF ultrafiltration membranes blending with PVA modified SiO2 hydrophilic nanoparticles
    Sun, De; Yue, Dongmin; Li, Bingbing; Zheng, Zhaoshan; Meng, Xiangchun
    Polymer Engineering & Science (2019), 59 (S1), E412-E421CODEN: PYESAZ; ISSN:0032-3888. (John Wiley & Sons, Inc.)
    In this study, PVA-SiO2 was synthesized by modifying silica (SiO2) with polyvinyl alc. (PVA), then a novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was prepd. by incorporating the prepd. PVA-SiO2 into membrane matrix using the non-solvent induced phase sepn. (NIPS) method. The effects of PVA-SiO2 particle on the properties of the PVDF membrane were systematically studied by scanning electron microscope (SEM), Fourier transform IR spectroscopy (FT-IR), surface pore size, porosity, and water contact angle. The results indicated that with the addn. of PVA-SiO2 particles in the PVDF UF membranes, membrane mean pore size increased from 80.06 to 126.00 nm, porosity improved from 77.4% to 89.1%, and water contact angle decreased from 75.61° to 63.10°. Furthermore, ultrafiltration expts. were conducted in terms of pure water flux, bovine serum albumin (BSA) rejection, and anti-fouling performance. It indicated that with the addn. of PVA-SiO2 particles, pure water flux increased from 70 to 126 L/m2 h, BSA rejection increased from 67% to 86%, flux recovery ratio increased from 60% to 96%, total fouling ratio decreased from 50% to 18.7%, and irreversible fouling ratio decreased from 40% to 4%. Membrane anti-fouling property was improved, and it can be expected that this work may provide some refs. to the improvement of the anti-fouling performance of the PVDF ultrafiltration membrane.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlemsrzO&md5=eb02cc5f80d92b294cf53821f37b08a8
  7. 7
    Benhabiles, O.; Galiano, F.; Marino, T.; Mahmoudi, H.; Lounici, H.; Figoli, A. Preparation and Characterization of TiO2-PVDF/PMMA Blend Membranes Using an Alternative Non-Toxic Solvent for UF/MF and Photocatalytic Application. Molecules 2019, 24, 724  DOI: 10.3390/molecules24040724
    Google Scholar
    7
    Preparation and characterization of TiO2-PVDF/PMMA blend membranes using an alternative non-toxic solvent for UF/MF and photocatalytic application
    Benhabiles, Ouassila; Galiano, Francesco; Marino, Tiziana; Mahmoudi, Hacene; Lounici, Hakim; Figoli, Alberto
    Molecules (2019), 24 (4), 724CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)
    The approach of the present work is based on the use of poly (methylmethacrylate) (PMMA) polymer, which is compatible with PVDF and TiO2 nanoparticles in casting solns., for the prepn. of nano-composites membranes using a safer and more compatible solvent. TiO2 embedded poly (vinylidene fluoride) (PVDF)/PMMA photocatalytic membranes were prepd. by phase inversion method. A non-solvent induced phase sepn. (NIPS) coupled with vapor induced phase sepn. (VIPS) was used to fabricate flat-sheet membranes using a dope soln. consisting of PMMA, PVDF, TiO2, and tri-Et phosphate (TEP) as an alternative non-toxic solvent. Membrane morphol. was examd. by SEM (SEM). Backscatter electron detector (BSD) mapping was used to monitor the inter-dispersion of TiO2 in the membrane surface and matrix. The effects of polymer concn., evapn. time, additives and catalyst amt. on the membrane morphol. and properties were investigated. Tests on photocatalytic degrdn. of methylene blue (MB) were also carried out using the membranes entrapped with different concns. of TiO2. The results of this study showed that nearly 99% MB removal can be easily achieved by photocatalysis using TiO2 immobilized on the membrane matrix. Moreover, it was obsd. that the quantity of TiO2 plays a significant role in the dye removal.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXoslensLY%253D&md5=d7627fa6556c9979f7f97c636ac91888
  8. 8
    Wang, S.; Li, T.; Chen, C.; Chen, S.; Liu, B.; Crittenden, J. Non-woven PET fabric reinforced and enhanced the performance of ultrafiltration membranes composed of PVDF blended with PVDF-g-PEGMA for industrial applications. Appl. Surf. Sci. 2018, 435, 1072– 1079,  DOI: 10.1016/j.apsusc.2017.11.193
    Google Scholar
    8
    Non-woven PET fabric reinforced and enhanced the performance of ultrafiltration membranes composed of PVDF blended with PVDF-g-PEGMA for industrial applications
    Wang, Shuai; Li, Tong; Chen, Chen; Chen, Sheng; Liu, Baicang; Crittenden, John
    Applied Surface Science (2018), 435 (), 1072-1079CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
    Ultrafiltration (UF) membranes composed of poly(vinylidene fluoride) (PVDF) blended with poly(vinylidene fluoride)-graft-poly(ethylene glycol) Me ether methacrylate (PVDF-g-PEGMA) can present high flux and excellent foulant removal efficiencies under suitable prepn. conditions. However, these PVDF/PVDF-g-PEGMA blended membranes cannot be applied industrially because of the insufficient mech. strength (strength-to-break value of 8.4 ± 0.6 MPa). We incorporated two types of non-woven polyethylene terephthalate (PET) fabrics (thin hydrophobic and thick hydrophilic fabrics) as support layers to improve the mech. properties of the blended membranes. The thin and thick PET fabrics were able to significantly improve the tensile strength to 23.3 ± 3.7 MPa and 30.1 ± 1.4 MPa, resp. The PET fabrics had a limited impact on the sepn.-related membrane performance such as hydrophilicity, foulant rejection, whereas the mech. strength and pure water flux was improved several folds. The enhanced flux was attributed to the higher surface porosity and wider finger-like voids in the cross-section. The thin PET fabric with larger porosity was able to maintain a consistent toughness simultaneously; thus it is recommended as a support material for this blended membrane.
    >> More from SciFinder ®
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  9. 9
    Venault, A.; Chang, C.-Y.; Tsai, T.-C.; Chang, H.-Y.; Bouyer, D.; Lee, K.-R.; Chang, Y. Surface zwitterionization of PVDF VIPS membranes for oil and water separation. J. Membr. Sci. 2018, 563, 54– 64,  DOI: 10.1016/j.memsci.2018.05.049
    Google Scholar
    9
    Surface zwitterionization of PVDF VIPS membranes for oil and water separation
    Venault, Antoine; Chang, Chia-Yu; Tsai, Tai-Chun; Chang, Hsiang-Yu; Bouyer, Denis; Lee, Kueir-Rarn; Chang, Yung
    Journal of Membrane Science (2018), 563 (), 54-64CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    This work aims at applying a combined polymn. and membrane surface-modification process, in order to hydrophilize poly(vinylidene fluoride) membranes prepd. by vapor-induced phase sepn. (VIPS), and eventually make them suitable for low transmembrane pressure (ΔP = 0.5bar) membrane sepn. of various oil-in-water (O/W) emulsions. Styrene and sulfobetaine monomers were mixed and allowed to react while the PVDF membrane was in contact with the reactive mixt., enabling self-assembling of the random polymer on the membrane as it was formed. Reaction parameters were optimized, and it was found that a solid content of 5wt%, a styrene/SBMA ratio of 40/60 and a reaction time of 5h led to very hydrophilic membrane (water contact angle: 12°). The combination of chem. analyses evidenced the successful and controlled surface modification process. Phys. analyses showed that deviating from the optimized conditions of styrene/SBMA ratio led to the formation of agglomerates (styrene-rich or SBMA-rich), assocd. to low porosity, and high coating d. The membranes were used to sep. emulsions of toluene/W, hexane/W, hexadecane/W, diesel/W and soybean oil/W, leading to sepn. efficiency of 99.0%, 99.2%, 99.1%, 99.0% and 99.0%, resp. This work thus presents a new avenue for surface modification of membrane with extremely efficient copolymers for which there is no common solvent, and brings several evidences of the suitability of VIPS membrane for cost-effective membrane sepn. of various emulsions.
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  10. 10
    Younas, H.; Bai, H.; Shao, J.; Han, Q.; Ling, Y.; He, Y. Super-hydrophilic and fouling resistant PVDF ultrafiltration membranes based on a facile prefabricated surface. J. Membr. Sci. 2017, 541, 529– 540,  DOI: 10.1016/j.memsci.2017.07.035
    Google Scholar
    10
    Super-hydrophilic and fouling resistant PVDF ultrafiltration membranes based on a facile prefabricated surface
    Younas, Hassan; Bai, Hongwei; Shao, Jiahui; Han, Qiaochu; Ling, Yuhan; He, Yiliang
    Journal of Membrane Science (2017), 541 (), 529-540CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    The hydrophilicity of PVDF membrane is playing an enormously important role in its widespread water treatment fields considering the excellent intrinsic properties of PVDF raw materials. Rather than the conventional surface modification or hybridization, herein, we report a novel approach to prep. super-hydrophilic PVDF ultrafiltration (UF) membrane by creating a prefabricated super-hydrophilic surface of inorg. TiO2 nanoparticles (NPs). The resultant membrane [prepd. by prefabrication surface adhesion of TiO2 NPs on PVDF-PEG-TiO2 hybrid membrane (SaT-PPT)] has a uniform distribution of TiO2 NPs not only on the membrane surface but also within membrane matrix, this will maximize the super-hydrophilic feature throughout the membrane: from inner porous structures to outer surfaces, and will avoid "dead-corner" to block fast water pass through. The performances of SaT-PPT membrane as compared with the control membranes (PVDF-PEG, and PVDF-PEG with TiO2 anchored only at surface) were investigated in terms of humic acid (HA) rejection, flux and flux decline in lab.-made cross flow UF expts. with and without UV irradn. It indicated that SaT-PPT membrane exhibited the highest hydrophilicity and flux, lowest flux decline and total resistance, but still with the highest HA rejection rate. In addn., SaT-PPT membrane showed the highest flux recovery after simple phys. cleaning to extend the longer life span of membrane. It is reasonable to believe that our developed SaT-PPT membranes will provide insightful engineering practices to benefit the broad water treatment applications.
    >> More from SciFinder ®
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  11. 11
    Liu, C.; Wu, L.; Zhang, C.; Chen, W.; Luo, S. Surface hydrophilic modification of PVDF membranes by trace amounts of tannin and polyethyleneimine. Appl. Surf. Sci. 2018, 457, 695– 704,  DOI: 10.1016/j.apsusc.2018.06.131
    Google Scholar
    11
    Surface hydrophilic modification of PVDF membranes by trace amounts of tannin and polyethyleneimine
    Liu, Cong; Wu, Lili; Zhang, Chaocan; Chen, Wanyu; Luo, Shuo
    Applied Surface Science (2018), 457 (), 695-704CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
    A com. PVDF Microfiltration (MF) membrane was surface modified via a simple coating method for improvement of the hydrophilicity and anti-fouling performance. Herein, trace amts. of tannin acid (TA) and Polyethyleneimine (PEI) were firstly used with (3-Chloropropyl)trimethoxysilan (CTS) to endow the PVDF membranes with hydrophilicity. The physicochem. property of the modified membranes was characterized by SEM, AFM, ATR-FTIR and XPS resp., and a series of tests including water contact angle (WCA), underwater oil contact angle (OCA), pure water flux (PWF), anti-fouling expts. and so on were utilized to inspect the modified effect. Benefiting from the interactions among CTS, PEI and TA, several coating layers formed on the surface of the membranes and remarkable hydrophilicity with water contact angle of 16° was obtained, moreover, the pure water flux of this composite membranes could reach 10,782 L/M2·h.
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  12. 12
    Zeng, K.; Zhou, J.; Cui, Z.; Zhou, Y.; Shi, C.; Wang, X.; Zhou, L.; Ding, X.; Wang, Z.; Drioli, E. Insight into fouling behavior of poly(vinylidene fluoride) (PVDF) hollow fiber membranes caused by dextran with different pore size distributions. Chin. J. Chem. Eng. 2018, 26, 268– 277,  DOI: 10.1016/j.cjche.2017.04.008
    Google Scholar
    12
    Insight into fouling behavior of poly(vinylidene fluoride) (PVDF) hollow fiber membranes caused by dextran with different pore size distributions
    Zeng, Kailiang; Zhou, Jie; Cui, Zhaoliang; Zhou, Yue; Shi, Chuan; Wang, Xiaozu; Zhou, Liyue; Ding, Xiaobin; Wang, Zhaohui; Drioli, Enrico
    Chinese Journal of Chemical Engineering (2018), 26 (2), 268-277CODEN: CJCEEB; ISSN:1004-9541. (Chemical Industry Press)
    Membrane fouling is the key problem that occurs in membrane process for water treatment. However, how membrane microstructure influences the fouling behavior is still not clear. In this study, fouling behavior caused by dextran was deeply and systematically investigated by employing four poly(vinylidene fluoride) (PVDF) membranes with different pore sizes, ranging from 24 to 94 nm. The extent of fouling by dextran was accurately characterized by pore redn., flux decline, and the change of crit. flux. The result shows that membrane with the smallest pore size of 24 nm experienced the smallest fouling rate and the lowest fouling extent. As the membrane pore size increased, the crit. flux ranges were 105-114, 63-73, 38-44 and 34-43 L·m-2·h-1, resp. The crit. flux and fouling resistances indicated that the fouling propensity increases with the increase of membrane pore size. Two pilot membrane modules with mean pore size of 25 nm and 60 nm were applied in membrane filtration of surface water treatment. The results showed that serious irreversible membrane fouling occurred on the membrane with pore size of 60 nm at the permeate flux of 40.5 L·m-2·h-1. On the other hand, membrane with pore size of 25 nm exhibited much better anti-fouling performance when permeate flux was set to 40.5, 48 and 60 L·m-2·h-1.
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  13. 13
    Jayalakshmi, A.; Rajesh, S.; Mohan, D. Fouling propensity and separation efficiency of epoxidated polyethersulfone incorporated cellulose acetate ultrafiltration membrane in the retention of proteins. Appl. Surf. Sci. 2012, 258, 9770– 9781,  DOI: 10.1016/j.apsusc.2012.06.028
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    13
    Fouling propensity and separation efficiency of epoxidated polyethersulfone incorporated cellulose acetate ultrafiltration membrane in the retention of proteins
    Jayalakshmi, A.; Rajesh, S.; Mohan, D.
    Applied Surface Science (2012), 258 (24), 9770-9781CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
    Epoxidated polyethersulfone (EPES) incorporated cellulose acetate (CA) ultrafiltration membranes were prepd. by diffusion induced pptn. technique in the absence and presence of pore former polyethyleneglycol-600. Effect of blend ratio on the compatibility, thermal stability, mech. strength, hydrophilicity, morphol., pure water flux, protein adsorption resistance, protein sepn. efficiency and fouling propensity of the CA/EPES blend membranes was evaluated. Addn. of EPES gave thin sepg. layer and spongy sub layer in CA/EPES blend membranes. The efficiency of these membranes in the sepn. of com. important proteins such as bovine serum albumin, egg albumin, pepsin and trypsin was studied and is enhanced as compared to CA membranes. The fouling-resistant capability of the membranes was studied by bovine serum albumin as the model foulant and flux recovery ratio of the membranes were calcd. Attempts have been made to correlate the changes in membrane morphol. with pure water flux, hydraulic resistance, thermal and mech. stability, sepn. efficiency and antifouling property of the CA/EPES membranes. The optimal combination of CA and EPES thus gave high performance UF membranes which are sufficiently dense to retain proteins and at the same time give economically viable fluxes.
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  14. 14
    Rajesh, S.; Jayalakshmi, A.; Senthilkumar, S.; Sankar, H. S. H.; Mohan, D. R. Performance Evaluation of Poly(amide-imide) Incorporated Cellulose Acetate Ultrafiltration Membranes in the Separation of Proteins and Its Fouling Propensity by AFM Imaging. Ind. Eng. Chem. Res. 2011, 50, 14016– 14029,  DOI: 10.1021/ie201181h
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    14
    Performance Evaluation of Poly(amide-imide) Incorporated Cellulose Acetate Ultrafiltration Membranes in the Separation of Proteins and Its Fouling Propensity by AFM Imaging
    Rajesh, Sahadevan; Jayalakshmi, Ayyavoo; Senthilkumar, Sundararaj; Sankar, H. S. Hari; Mohan, Doraiswamy R.
    Industrial & Engineering Chemistry Research (2011), 50 (24), 14016-14029CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
    Polymeric membranes intended to be used in protein sepn. must be fouling resistant to reduce the interactions with proteins during operation. Therefore, cellulose acetate (CA) membranes with superior properties were prepd. by phase inversion technique using high-performance thermoplastic poly(amide-imide) (PAI) as the modification agent. The prepd. membranes were characterized using attenuated total reflectance Fourier transform IR spectroscopy (ATR-FTIR), SEM, at. force microscopy (AFM), mol. wt. cutoff, and pore size to investigate the influence of PAI on the properties of the resultant membranes. Intermol. interactions between the components in blend membranes were established by ATR-FTIR and SEM anal. showed that the blend CA membranes have thinner top layer and higher porosity in the sublayer. These prepd. membranes were subjected to the sepn. of proteins such as bovine serum albumin, egg albumin, pepsin, and trypsin. The fouling-resistant capability of the membranes was studied by bovine serum albumin as the model protein and increase in resistance during protein filtration was calcd. by resistance in series model anal. The fouled membranes were characterized by AFM imaging and these membranes were cleaned by washing with deionized water and subsequent sonication. From the AFM images of the fouled membranes it was clear that preferential adsorption takes place at specific locations on the membrane surface and is a function of surface roughness and membrane hydrophilicity. It is worth mentioning that the incorporation of poly(amide-imide) into the cellulose acetate matrix is an effective method for the development of low fouling ultrafiltration membranes for the sepn. of proteins.
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  15. 15
    Behboudi, A.; Jafarzadeh, Y.; Yegani, R. Polyvinyl chloride/polycarbonate blend ultrafiltration membranes for water treatment. J. Membr. Sci. 2017, 534, 18– 24,  DOI: 10.1016/j.memsci.2017.04.011
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    15
    Polyvinyl chloride/polycarbonate blend ultrafiltration membranes for water treatment
    Behboudi, A.; Jafarzadeh, Y.; Yegani, R.
    Journal of Membrane Science (2017), 534 (), 18-24CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    In this study, PVC/PC blend membranes were prepd. via NIPS methods. Characterization techniques including FESEM, XRD, DSC, contact angle measurement, mech. properties, abrasion test, stability test, pure water flux and filtration of BSA soln. were applied to investigate the effects of PC content on the structure and performance of blend membranes. It was shown than PVC and PC are compatible and the results of FESEM, XRD and DSC analyses confirmed their compatibility. The pore size distribution of membranes shifted toward smaller pores as the content of PC in the membranes increased up to 50% and then shifted back toward larger pores. In addn., hydrophilicity, tensile strength and abrasion resistance of the blend membranes were improved. However, chem. stability of membranes against NaOH soln. after 10 days decreased by increasing PC content. Pure water flux and BSA rejection as the performance criteria of membranes improved due to the presence of PC. It was found that antifouling properties of membranes increased with increasing PC content. The results indicated that PVC/PC blend membranes were high performance and fouling resistant membranes in comparison with neat PVC membrane.
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  16. 16
    Ma, W.; Rajabzadeh, S.; Shaikh, A. R.; Kakihana, Y.; Sun, Y.; Matsuyama, H. Effect of type of poly(ethylene glycol) (PEG) based amphiphilic copolymer on antifouling properties of copolymer/poly(vinylidene fluoride) (PVDF) blend membranes. J. Membr. Sci. 2016, 514, 429– 439,  DOI: 10.1016/j.memsci.2016.05.021
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    16
    Effect of type of poly(ethylene glycol) (PEG) based amphiphilic copolymer on antifouling properties of copolymer/poly(vinylidene fluoride) (PVDF) blend membranes
    Ma, Wenzhong; Rajabzadeh, Saeid; Shaikh, Abdul Rajjak; Kakihana, Yuriko; Sun, Yuchen; Matsuyama, Hideto
    Journal of Membrane Science (2016), 514 (), 429-439CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    The antifouling properties of poly(vinylidene fluoride) (PVDF) membranes were investigated by blending several types of synthesized amphiphilic poly(poly(ethylene glycol) Me ether methacrylate- Me methacrylate) [P(PEGMA- MMA)] copolymers with different initial PEGMA/MMA monomer ratios and PEG side chain lengths. Many types of membranes were prepd. using different copolymer/PVDF blend ratios via nonsolvent induced phase sepn. The membranes with similar pure water permeabilities and surface pore sizes were prepd. by controlling the dope soln. compn. Thus, the bovine serum albumin antifouling properties could be assessed under similar hydrodynamic filtration conditions. The membrane hydrophilicity, surface PEGMA coverage, and antifouling properties of the prepd. membranes increased with increasing copolymer/PVDF ratio and PEGMA/MMA monomer ratio of the copolymers and PEG length of the copolymer. A mol. dynamics simulation was performed to assess the surface chem. compn., and the results were compared with those of XPS. The antifouling properties depended more strongly on the membrane surface hydrophilicity when the copolymer chem. structures, i.e., the PEGMA/MMA monomer ratio and PEG side chain length, were changed, rather than when the copolymer/PVDF blend ratio was changed.
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  17. 17
    Hashim, N. A.; Liu, F.; Abed, M. R. M.; Li, K. Chemistry in spinning solutions: Surface modification of PVDF membranes during phase inversion. J. Membr. Sci. 2012, 415, 399– 411,  DOI: 10.1016/j.memsci.2012.05.024
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    There is no corresponding record for this reference.
  18. 18
    Wu, H.; Li, T.; Liu, B.; Chen, C.; Wang, S.; Crittenden, J. C. Blended PVC/PVC-g-PEGMA ultrafiltration membranes with enhanced performance and antifouling properties. Appl. Surf. Sci. 2018, 455, 987– 996,  DOI: 10.1016/j.apsusc.2018.06.056
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    18
    Blended PVC/PVC-g-PEGMA ultrafiltration membranes with enhanced performance and antifouling properties
    Wu, Haibo; Li, Tong; Liu, Baicang; Chen, Chen; Wang, Shuai; Crittenden, John C.
    Applied Surface Science (2018), 455 (), 987-996CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
    To improve the performance of poly(vinyl chloride) (PVC) membranes, we synthesized the amphiphilic copolymer PVC-graft-poly(ethylene glycol) Me ether methacrylate (PVC-g-PEGMA) via atom transfer radical polymn. (ATRP). We then fabricated PVC/PVC-g-PEGMA blended ultrafiltration membranes for the first time. The effect of the amt. of PVC-g-PEGMA from 5 to 20wt.% on the PVC membrane properties was systematically investigated. The successful synthesis of PVC-g-PEGMA was confirmed by the results of NMR (1H NMR), and Fourier transform IR spectroscopy (FTIR). With the increase in the amt. of the PVC-g-PEGMA additive from 0 to 20wt.%, we found that (1) the surface oxygen content of the membrane increased from 3.20% to 9.31%; (2) the membrane surface pore size and pore d. decreased; (3) the hydrophilicity and pure water flux of the membrane improved, but they plateaued, even slightly decreasing after the addn. of 15wt.% PVC-g-PEGMA; (4) the sodium alginate (SA) rejection ratios of all PVC/PVC-g-PEGMA blended membranes were higher than 90%; and (5) all blended PVC membranes exhibited higher flux recovery ratios (FRRs) than the pure PVC membrane; in particular, the FRR increased by 89% when 10wt.% PVC-g-PEGMA was added. These results indicated the enhanced antifouling properties of PVC/PVC-g-PEGMA blended ultrafiltration membranes.
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  19. 19
    Yang, B.; Yang, X.; Liu, B.; Chen, Z.; Chen, C.; Liang, S.; Chu, L.-Y.; Crittenden, J. PVDF blended PVDF-g-PMAA pH-responsive membrane: Effect of additives and solvents on membrane properties and performance. J. Membr. Sci. 2017, 541, 558– 566,  DOI: 10.1016/j.memsci.2017.07.045
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    19
    PVDF blended PVDF-g-PMAA pH-responsive membrane: Effect of additives and solvents on membrane properties and performance
    Yang, Boxuan; Yang, Xin; Liu, Baicang; Chen, Zhiqiang; Chen, Chen; Liang, Songmiao; Chu, Liang-Yin; Crittenden, John
    Journal of Membrane Science (2017), 541 (), 558-566CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Poly(vinylidene fluoride) (PVDF) and its deriv. copolymer PVDF-graft-poly(methacrylic acid) (PVDF-g-PMAA) were blended to prep. pH-responsive membranes. The effects of the following factors on stimuli-responsive membrane performance were systematically examd.: (1) amt. of PVDF-g-PMAA additives, (2) extent of purifn., (3) concn. of polymer, (4) addn. of poly(ethylene glycol) (PEG), and (5) type of solvent. Field-emission SEM (FESEM), contact angle goniometry, at. force microscopy (AFM), attenuated total reflection Fourier transform IR (ATR-FTIR) spectroscopy, XPS, flux and solute rejection performance were used to characterize our fabricated membranes. We found that partially purified PVDF-g-PMAA membrane contains more surface PMAA than the purified one (purified signifies that excess unreacted species were removed). In addn., a much higher flux performance and pH-responsive coeff. were found for the partially purified PVDF-g-PMAA membranes; consequently, membranes were only partially purified throughout our work. The flux of the pH-responsive membranes is dramatically increased by decreasing the polymer concn. from 18 wt% to 15 wt% and by adding PEG and PVDF-g-PMAA. We could create a tunable broad range flux from ∼ 1 to 1200 L/m2 h by adjusting the polymer concn., adding PEG and PVDF-g-PMAA, and using different solvents. Our tunable approach has great potential for various applications (e.g., water treatment and food processing).
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  20. 20
    Hester, J. F.; Banerjee, P.; Won, Y. Y.; Akthakul, A.; Acar, M. H.; Mayes, A. M. ATRP of amphiphilic graft copolymers based on PVDF and their use as membrane additives. Macromolecules 2002, 35, 7652– 7661,  DOI: 10.1021/ma0122270
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    20
    ATRP of Amphiphilic Graft Copolymers Based on PVDF and Their Use as Membrane Additives
    Hester, J. F.; Banerjee, P.; Won, Y.-Y.; Akthakul, A.; Acar, M. H.; Mayes, A. M.
    Macromolecules (2002), 35 (20), 7652-7661CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    The direct prepn. of amphiphilic graft copolymers from com. poly(vinylidene fluoride) (PVDF) using atom transfer radical polymn. (ATRP) is demonstrated. Here, direct initiation of the secondary fluorinated site of PVDF facilitates grafting of the hydrophilic comonomer. Amphiphilic comb copolymer derivs. of PVDF having poly(methacrylic acid) side chains (PVDF-g-PMAA) and poly(oxyethylene methacrylate) side chains (PVDF-g-POEM) are prepd. using this method. Surface segregation of PVDF-g-POEM additives in PVDF is examd. as a route to wettable, foul-resistant surfaces on PVDF filtration membranes. Because of surface segregation during the std. immersion pptn. process for membrane fabrication, a PVDF/5 wt. % PVDF-g-POEM membrane, having a bulk POEM concn. of 3.4 wt. %, exhibits a near-surface POEM concn. of 42 wt. % as measured by XPS. This membrane displays substantial resistance to BSA fouling compared with pure PVDF and wets spontaneously when placed in contact with water.
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  21. 21
    Ran, J.; Wu, L.; Zhang, Z.; Xu, T. Atom transfer radical polymerization (ATRP): A versatile and forceful tool for functional membranes. Prog. Polym. Sci. 2014, 39, 124– 144,  DOI: 10.1016/j.progpolymsci.2013.09.001
    Google Scholar
    21
    Atom transfer radical polymerization (ATRP): A versatile and forceful tool for functional membranes
    Ran, Jin; Wu, Liang; Zhang, Zhenghui; Xu, Tongwen
    Progress in Polymer Science (2014), 39 (1), 124-144CODEN: PRPSB8; ISSN:0079-6700. (Elsevier Ltd.)
    A review. The progress in atom transfer radical polymn. (ATRP) provides an effective means for the design and prepn. of functional membranes. Polymeric membranes with different macromol. architectures applied in fuel cells, including block and graft copolymers are conveniently prepd. via ATRP. Moreover, ATRP has also been widely used to introduce functionality onto the membrane surface to enhance its use in specific applications, such as antifouling, stimuli-responsive, adsorption function and pervaporation. In this review, the recent design and synthesis of advanced functional membranes via the ATRP technique are discussed in detail and their especial advantages are highlighted by selected examples ext. the principles for prepn. or modification of membranes using the ATRP methodol.
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  22. 22
    Xu, F. J.; Zhao, J. P.; Kang, E. T.; Neoh, K. G.; Li, J. Functionalization of nylon membranes via surface-initiated atom-transfer radical polymerization. Langmuir 2007, 23, 8585– 8592,  DOI: 10.1021/la7011342
    Google Scholar
    22
    Functionalization of Nylon Membranes via Surface-Initiated Atom-Transfer Radical Polymerization
    Xu, F. J.; Zhao, J. P.; Kang, E. T.; Neoh, K. G.; Li, J.
    Langmuir (2007), 23 (16), 8585-8592CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    The ability to manipulate and control the surface properties of nylons is of crucial importance to their widespread applications. In this work, surface-initiated atom-transfer radical polymn. (ATRP) is employed to tailor the functionality of the nylon membrane and pore surfaces in a well-controlled manner. A simple two-step method, involving the activation of surface amide groups with formaldehyde and the reaction of the resulting N-methylol polyamide with 2-bromoisobutyryl bromide, was first developed for the covalent immobilization of ATRP initiators on the nylon membrane and its pore surfaces. Functional polymer brushes of 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol)monomethacrylate (PEGMA) were prepd. via surface-initiated ATRP from the nylon membranes. A kinetics study revealed that the chain growth from the membranes was consistent with a "controlled" process. The dormant chain ends of the grafted HEMA polymer (P(HEMA)) and PEGMA polymer (P(PEGMA)) on the nylon membranes could be reactivated for the consecutive surface-initiated ATRP to produce the corresponding nylon membranes functionalized by P(HEMA)-b-P(PEGMA) and P(PEGMA)-b-P(HEMA) diblock copolymer brushes. In addn., membranes with grafted P(HEMA) and P(PEGMA) brushes exhibited good resistance to protein adsorption and fouling under continuous-flow conditions.
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  23. 23
    Zhou, Z.; Rajabzadeh, S.; Shaikh, A. R.; Kakihana, Y.; Ma, W.; Matsuyama, H. Effect of surface properties on antifouling performance of poly(vinyl chloride-co-poly(ethylene glycol)methyl ether methacrylate)/PVC blend membrane. J. Membr. Sci. 2016, 514, 537– 546,  DOI: 10.1016/j.memsci.2016.05.008
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    23
    Effect of surface properties on antifouling performance of poly(vinyl chloride-co-poly(ethylene glycol)methyl ether methacrylate)/PVC blend membrane
    Zhou, Zhuang; Rajabzadeh, Saeid; Shaikh, Abdul Rajjak; Kakihana, Yuriko; Ma, Wenzhong; Matsuyama, Hideto
    Journal of Membrane Science (2016), 514 (), 537-546CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Several membranes with low fouling properties were prepd. by blending PVC with poly(vinyl chloride-co-poly(ethylene glycol) Me ether methacrylate) (poly(VC-co-PEGMA)) copolymer via a non-solvent induced phase sepn. (NIPS) method. Bovine serum albumin adsorption on polymer films decreased and the membrane surface pore sizes, hydrophilicities, and antifouling properties increased on increasing the poly(VC-co-PEGMA)/PVC blending ratio. Membrane surface PEGMA coverage increased on increasing the poly(VC-co-PEGMA)/PVC blending ratio, resulting in higher hydrophilicities and lower fouling propensities. Membranes with similar water permeabilities were prepd. by adjusting the dope soln. compn. to eliminate the effect of hydrodynamic conditions on membrane fouling performance. The effect of the membrane material on the membrane fouling propensity was much stronger than that of the membrane surface structure. Mol. dynamics simulations were performed to evaluate the surface chem. compn. of the membrane matrix and results were compared with results obtained from XPS measurements.
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  24. 24
    Matyjaszewski, K. Advanced Materials by Atom Transfer Radical Polymerization. Adv. Mater. 2018, 30, 1706441  DOI: 10.1002/adma.201706441
    Google Scholar
    There is no corresponding record for this reference.
  25. 25
    Matyjaszewski, K. Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives. Macromolecules 2012, 45, 4015– 4039,  DOI: 10.1021/ma3001719
    Google Scholar
    25
    Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives
    Matyjaszewski, Krzysztof
    Macromolecules (Washington, DC, United States) (2012), 45 (10), 4015-4039CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    A review. Current status and future perspectives in atom transfer radical polymn. (ATRP) are presented. Special emphasis is placed on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP. New hybrid materials based on org./inorg. systems and natural/synthetic polymers are presented. Some current and forthcoming applications are described.
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  26. 26
    Bhattacharya, A.; Misra, B. N. Grafting: a versatile means to modify polymers - Techniques, factors and applications. Prog. Polym. Sci. 2004, 29, 767– 814,  DOI: 10.1016/j.progpolymsci.2004.05.002
    Google Scholar
    26
    Grafting: a versatile means to modify polymers. Techniques, factors and applications
    Bhattacharya, A.; Misra, B. N.
    Progress in Polymer Science (2004), 29 (8), 767-814CODEN: PRPSB8; ISSN:0079-6700. (Elsevier B.V.)
    A review on graft copolymn. initiated by chem. treatment, photoirradn., high-energy radiation, and other means is given. Several prime controlling factors on grafting are discussed. Grafting is used in polymers for membrane sepn. and prodn. of conducting polymers.
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  27. 27
    Chang, Y.; Ko, C.-Y.; Shih, Y.-J.; Quemener, D.; Deratani, A.; Wei, T.-C.; Wang, D.-M.; Lai, J.-Y. Surface grafting control of PEGylated poly(vinylidene fluoride) antifouling membrane via surface-initiated radical graft copolymerization. J. Membr. Sci. 2009, 345, 160– 169,  DOI: 10.1016/j.memsci.2009.08.039
    Google Scholar
    27
    Surface grafting control of PEGylated poly(vinylidene fluoride) antifouling membrane via surface-initiated radical graft copolymerization
    Chang, Yung; Ko, Chao-Yin; Shih, Yu-Ju; Quemener, Damien; Deratani, Andre; Wei, Ta-Chin; Wang, Da-Ming; Lai, Juin-Yih
    Journal of Membrane Science (2009), 345 (1-2), 160-169CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    This work describes the surface grafting control of poly(vinylidene fluoride) (PVDF) membrane with poly(ethylene glycol) methacrylate (PEGMA) via three different modification approaches of surface-initiated radical graft copolymn., including thermal-induced radical polymn., surface-initiated atom transfer radical polymn. (ATRP), and low pressure plasma-induced graft-polymn. Two different surface grafting structures of PEGylated layer, brush-like PEGMA and network-like PEGMA, on PVDF membrane surface were achieved in this study. The chem. compn. and microstructure of the various surface-modified PEGylated PVDF membranes were characterized by Fourier transform IR spectroscopy (FT-IR), contact angle, at. force microscopy (AFM), and XPS measurements. Antifouling property of the modified PVDF membranes was evaluated according to the amt. of protein adsorption and the filtration test for BSA soln. in this study. Results show that the amt. of adsorbed proteins on the modified PVDF membranes not only depends on the surface hydrophilicity and hydration capacity but also assocs. with the surface grafting structures of PEGylated layers on PVDF membrane surface. This study not only introduces different practical modification approaches to achieve a hydrophobic PVDF membrane grafting hydrophilic PEGMA, but also provides a fundamental understanding of various PEGylated grafting structures governing the performance of antifouling properties.
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  28. 28
    Liu, B.; Chen, C.; Li, T.; Crittenden, J.; Chen, Y. High performance ultrafiltration membrane composed of PVDF blended with its derivative copolymer PVDF-g-PEGMA. J. Membr. Sci. 2013, 445, 66– 75,  DOI: 10.1016/j.memsci.2013.05.043
    Google Scholar
    28
    High performance ultrafiltration membrane composed of PVDF blended with its derivative copolymer PVDF-g-PEGMA
    Liu, Baicang; Chen, Chen; Li, Tong; Crittenden, John; Chen, Yongsheng
    Journal of Membrane Science (2013), 445 (), 66-75CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Amphiphilic graft copolymers were fabricated from a poly(vinylidene fluoride) (PVDF) backbone that was grafted with poly(ethylene glycol) Me ether methacrylate (PEGMA) (PVDF-g-PEGMA) using atom transfer radical polymn. (ATRP) method. An intriguing membrane of periodic pillar-like or sphere structures was formed using PVDF/PVDF-g-PEGMA block copolymer mixts. that were dissolved in suitable solvents. XPS, SEM, at. force microscopy (AFM), contact angle measurement, and flux performance tests were conducted to det. the membrane characteristics. The results show that the defect-free high performance ultrafiltration membrane can be fabricated by adding 10 wt% or 15 wt% PVDF-g-PEGMA to the PVDF backbone material using the phase inversion method. The permeate fluxes of the fabricated membrane with 10 wt% and 15 wt% PVDF534K-g-PEGMA are 5110 (L/m2 h bar) and 5170 (L/m2 h bar), resp., for deionized water under 0.07 MPa. The TOC (sodium alginate) removal efficiencies of PVDF membranes with 10 wt%, and 15 wt% PVDF534K-g-PEGMA are 90.97%, and 87.19%, resp. Furthermore, the removals of Suwannee River humic acid that contained 2 mM CaCl2 and 10 mM Ca(OH)2 for the PVDF membrane with 10 wt% PVDF534K-g-PEGMA are 72.11% and 77.69%, resp. This defect-free high-performance membranes show good potential for water treatment applications.
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  29. 29
    Hashim, N. A.; Liu, F.; Li, K. A simplified method for preparation of hydrophilic PVDF membranes from an amphiphilic graft copolymer. J. Membr. Sci. 2009, 345, 134– 141,  DOI: 10.1016/j.memsci.2009.08.032
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    29
    A simplified method for preparation of hydrophilic PVDF membranes from an amphiphilic graft copolymer
    Hashim, N. Awanis; Liu, Fu; Li, K.
    Journal of Membrane Science (2009), 345 (1-2), 134-141CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    An attempt to reduce the no. of steps and hence the overall costs involved in the prepn. of hydrophilic flat sheet poly(vinylidene fluoride) (PVDF) membranes was made by adding PVDF polymer powders directly to an amphiphilic copolymer mixt. contg. PVDF grafted with poly(ethylene glycol) Me ether methacrylate (PEGMA) (PVDF-g-PEGMA), solvent and unreacted PEGMA from the atom transfer radical polymn. (ATRP) method. The membrane was characterized by Fourier transform infra-red attenuated reflection spectroscopy (FTIR-ATR), at. force microscopy (AFM), SEM and field emission SEM (FESEM), pure water flux, contact angle measurement and protein filtration expts. The presence of ester and ether groups attributable to the PEGMA in the resultant membrane was obsd. from FTIR-ATR spectra. From SEM and FESEM observations, an asym. membrane was formed with a thin skin layer accompanied by short finger-like and macrovoid structures, but the membrane morphol. changed when the copolymer content was increased. AFM reveals that the roughness of the membranes becomes greater with higher amt. of PVDF-g-PEGMA. The pure water permeation flux of the prepd. membrane increased significantly to 116 L/m2 h compared to pure PVDF membranes, while contact angle measurements show a moderate value of between 57° and 67°. The percentage of fouling recovered using water cleaning after protein filtration was found to be 100% for all membranes prepd. from this method. The results suggested that hydrophilic and low-fouling PVDF membranes were formed from the newly developed method. Since membrane hydrophilicity has a pronounced effect on the fouling properties, hydrophilic PVDF membranes developed from this process are anticipated to be suitable not only for bio-sepn., but also for wastewater treatment.
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  30. 30
    Chen, C.; Tang, L.; Liu, B.; Zhang, X.; Crittenden, J.; Chen, K. L.; Chen, Y. Forming mechanism study of unique pillar-like and defect-free PVDF ultrafiltration membranes with high flux. J. Membr. Sci. 2015, 487, 1– 11,  DOI: 10.1016/j.memsci.2015.03.075
    Google Scholar
    30
    Forming mechanism study of unique pillar-like and defect-free PVDF ultrafiltration membranes with high flux
    Chen, Chen; Tang, Li; Liu, Baicang; Zhang, Xiao; Crittenden, John; Chen, Kai Loon; Chen, Yongsheng
    Journal of Membrane Science (2015), 487 (), 1-11CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    An intriguing polyvinylidene fluoride (PVDF) membrane with unique pillar-like structures was synthesized. The membrane was synthesized using the phase inversion method by adding the amphiphilic graft copolymer PVDF grafted with poly(ethylene glycol) Me ether methacrylate (PEGMA) (PVDF-g-PEGMA) to the PVDF backbone material. It had high flux and high sodium alginate rejection ratio under low transmembrane pressure. However, the mechanisms for the formation of pillar-like structures are still unknown. In this paper, we explored the formation mechanism of pillar-like structures from aspects of solvent and additive. Based on the exptl. results and anal. of ternary diagram, both NMP and PVDF-g-PEGMA must coexist in casting soln. to form pillar-like structures. When NMP is in the solvent, PEGMA segments have enough time to migrate to the surface and repel each other during the phase inversion process. Finally, by using the target plot method, one membrane with the best performance was chosen as the proposed membrane from all membranes that casted under different conditions. The proposed membrane has a pure water flux of 2173 L/m2/h/bar. The total org. carbon (TOC, by sodium alginate) removal efficiency is 89%. This membrane may have a good potential in water treatment applications.
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  31. 31
    Wang, S.; Li, T.; Chen, C.; Liu, B.; Crittenden, J. C. PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times. Front. Environ. Sci. Eng. 2018, 12, 3,  DOI: 10.1007/s11783-017-0980-0
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    There is no corresponding record for this reference.
  32. 32
    Sheldon, R. A. Metrics of Green Chemistry and Sustainability: Past, Present, and Future. ACS Sustainable Chem. Eng. 2018, 6, 32– 48,  DOI: 10.1021/acssuschemeng.7b03505
    Google Scholar
    32
    Metrics of Green Chemistry and Sustainability: Past, Present, and Future
    Sheldon, Roger A.
    ACS Sustainable Chemistry & Engineering (2018), 6 (1), 32-48CODEN: ASCECG; ISSN:2168-0485. (American Chemical Society)
    A review concerning historic, current, and future green chem. and sustainability metrics for fine org. chem. and pharmaceutical prodn. is given. Topics discussed include: green chem. origins; catalysis soln. to pollution; mass-based green metrics (atom economy and the E [environmental] factor, other mass-based metrics, system boundaries and intrinsic E factors); sustainability metrics and the environmental impact of wastes (energy efficiency metrics, environmental impact of wastes, life cycle assessment); from environmental impact to sustainability (circular economy); the bio-based economy; and summary and future outlook.
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  33. 33
    Giraud, R. J.; Williams, P. A.; Sehgal, A.; Ponnusamy, E.; Phillips, A. K.; Manley, J. B. Implementing Green Chemistry in Chemical Manufacturing: A Survey Report. ACS Sustainable Chem. Eng. 2014, 2, 2237– 2242,  DOI: 10.1021/sc500427d
    Google Scholar
    33
    Implementing Green Chemistry in Chemical Manufacturing: A Survey Report
    Giraud, Robert J.; Williams, Paul A.; Sehgal, Amit; Ponnusamy, Ettigounder; Phillips, Alan K.; Manley, Julie B.
    ACS Sustainable Chemistry & Engineering (2014), 2 (10), 2237-2242CODEN: ASCECG; ISSN:2168-0485. (American Chemical Society)
    A review. Green chem. is being implemented in chem. manufg. to advance sustainability. A scouting survey and recent industry-wide reports find that several green chem. principles and related metrics are routinely being implemented in the chem. manufg. sector. A cross-section of stakeholders surveyed agree that broader adoption of the principles of green chem. can be promoted by collaboration among companies to identify best practices and define opportunities to increase green chem. implementation in chem. manufg. Active collaborative efforts to improve implementation include identifying common attributes of effective process metrics, developing means of tracking sector-wide implementation, and defining industrial needs for translating promising green chem. ideas into implementable, cost-effective, and low business risk technologies.
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  34. 34
    Clarke, C. J.; Tu, W. C.; Levers, O.; Brohl, A.; Hallett, J. P. Green and Sustainable Solvents in Chemical Processes. Chem. Rev. 2018, 118, 747– 800,  DOI: 10.1021/acs.chemrev.7b00571
    Google Scholar
    34
    Green and Sustainable Solvents in Chemical Processes
    Clarke, Coby J.; Tu, Wei-Chien; Levers, Oliver; Brohl, Andreas; Hallett, Jason P.
    Chemical Reviews (Washington, DC, United States) (2018), 118 (2), 747-800CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review. Sustainable solvents are a topic of growing interest in both the research community and the chem. industry due to a growing awareness of the impact of solvents on pollution, energy usage and contributions to air quality and climate change. Solvent losses represent a major portion of org. pollution and solvent removal represents a large proportion of process energy consumption. To counter these emerging issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Much of the focus has been on the environmental credentials of the solvent itself, though how a substance is deployed is as important to sustainability as what it is made from. In this review we consider several aspects of the most prominent sustainable org. solvents in use today - ionic liqs., deep eutectic solvents, supercrit. fluids, switchable solvents, liq. polymers and renewable solvents. We examine not only the performance of each class of solvent within the context of the reactions or extns. for which it is employed, but also give consideration to the wider context of the process and system within which the solvent is deployed. A wide range of tech., economic and environmental factors are considered, giving a more complete picture of the current status of sustainable solvent research and development.
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  35. 35
    Sheldon, R. A. The E factor 25 years on: the rise of green chemistry and sustainability. Green Chem. 2017, 19, 18– 43,  DOI: 10.1039/C6GC02157C
    Google Scholar
    35
    The E factor 25 years on: the rise of green chemistry and sustainability
    Sheldon, Roger A.
    Green Chemistry (2017), 19 (1), 18-43CODEN: GRCHFJ; ISSN:1463-9262. (Royal Society of Chemistry)
    The global impact, over the last 25 years, of the principles of green chem. and sustainability, and the pivotal role of the E factor concept in driving resource efficiency and waste minimisation, in the chem. and allied industries, is reviewed. Following an introduction to the origins of green chem. and the E factor concept, the various metrics for measuring greenness are discussed. It is emphasized that mass-based metrics such as atom economy, E factors and process mass intensity (PMI) need to be supplemented by metrics, in particular life cycle assessment, which measure the environmental impact of waste and, in order to assess sustainability, by metrics which measure economic viability. The role of catalysis in waste minimisation is discussed and illustrated with examples of green catalytic processes such as aerobic oxidns. of alcs., catalytic C-C bond formation and olefin metathesis. Solvent losses are a major source of waste in the pharmaceutical and fine chem. industries and solvent redn. and replacement strategies, including the possible use of neoteric solvents, such as ionic liqs. and deep eutectic solvents, are reviewed. Biocatalysis has many benefits in the context of green and sustainable chem. and this is illustrated with recent examples in the synthesis of active pharmaceutical ingredients. The importance of the transition from an unsustainable economy based on fossil resources to a sustainable bio-based economy is delineated, as part of the overarching transition from an unsustainable linear economy to a truly green and sustainable circular economy based on resource efficiency and waste minimisation by design.
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  36. 36
    Gałuszka, A.; Migaszewski, Z.; Namiesnik, J. The 12 principles of green analytical chemistry and the SIGNIFICANCE mnemonic of green analytical practices. TrAC, Trends Anal. Chem. 2013, 50, 78– 84,  DOI: 10.1016/j.trac.2013.04.010
    Google Scholar
    36
    The 12 principles of green analytical chemistry and the SIGNIFICANCE mnemonic of green analytical practices
    Galuszka, Agnieszka; Migaszewski, Zdzislaw; Namiesnik, Jacek
    TrAC, Trends in Analytical Chemistry (2013), 50 (), 78-84CODEN: TTAEDJ; ISSN:0165-9936. (Elsevier B. V.)
    A review. The current rapid development of green anal. chem. (GAC) requires clear, concise guidelines in the form of GAC principles that will be helpful in greening lab. practices. The existing principles of green chem. and green engineering need revision for their use in GAC because they do not fully meet the needs of anal. chem. Tn this article a set of 12 principles is proposed consisting of known concepts (i.e. redn. in the use of reagents and energy, and elimination of waste, risk and hazard) together with some new ideas (i.e. the use of natural reagents), which will be important for the future of GAC.
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  37. 37
    Liu, F.; Hashim, N. A.; Liu, Y.; Abed, M. R. M.; Li, K. Progress in the production and modification of PVDF membranes. J. Membr. Sci. 2011, 375, 1– 27,  DOI: 10.1016/j.memsci.2011.03.014
    Google Scholar
    37
    Progress in the production and modification of PVDF membranes
    Liu, Fu; Hashim, N. Awanis; Liu, Yutie; Abed, M. R. Moghareh; Li, K.
    Journal of Membrane Science (2011), 375 (1-2), 1-27CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    A review. This article provides a comprehensive overview of recent progress in the prodn. and modification of poly(vinylidene fluoride) (PVDF) membranes for liq.-liq. or liq.-solid sepn. The cryst. properties, thermal stability and chem. resistance were firstly considered in this review, followed by the prodn. methods of PVDF membranes. Various modification approaches for PVDF membranes were subsequently reviewed. Finally, in the light of the anticipated role of PVDF as a superior membrane material, future prospects on the prodn. and modification of PVDF membranes were suggested.
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  38. 38
    Yeow, M. L.; Liu, Y. T.; Li, K. Morphological study of poly(vinylidene fluoride) asymmetric membranes: Effects of the solvent, additive, and dope temperature. J. Appl. Polym. Sci. 2004, 92, 1782– 1789,  DOI: 10.1002/app.20141
    Google Scholar
    38
    Morphological study of poly(vinylidene fluoride) asymmetric membranes: effects of the solvent, additive, and dope temperature
    Yeow, M. L.; Liu, Y. T.; Li, K.
    Journal of Applied Polymer Science (2004), 92 (3), 1782-1789CODEN: JAPNAB; ISSN:0021-8995. (John Wiley & Sons, Inc.)
    Asym. poly(vinylidene fluoride) (PVDF) membranes were cast with com.-grade Kynar K760 polymer pellets and four different solvent systems: N,N-dimethylacetamide (DMAc), N,N-dimethylformamide, 1-methyl-2-pyrrolidone, and tri-Et phosphate. With a focus on the PVDF/DMAc system, the effects of various additives (i.e., ethanol, glycerol, lithium chloride, lithium perchlorate, and water) on the resulting membrane morphol. were studied. The membrane morphol. was examd. with SEM. The effect of the dope soln. temp. on the membrane morphol. was also studied for the various additives used.
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  39. 39
    Ali, I.; Bamaga, O. A.; Gzara, L.; Bassyouni, M.; Abdel-Aziz, M. H.; Soliman, M. F.; Drioli, E.; Albeirutty, M. Assessment of Blend PVDF Membranes, and the Effect of Polymer Concentration and Blend Composition. Membranes 2018, 8, 13,  DOI: 10.3390/membranes8010013
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    39
    Assessment of blend PVDF membranes, and the effect of polymer concentration and blend composition
    Ali, Imtiaz; Bamaga, Omar A.; Gzara, Lassaad; Bassyouni, M.; Abdel-Aziz, M. H.; Soliman, M. F.; Drioli, Enrico; Albeirutt, Mohammed
    Membranes (Basel, Switzerland) (2018), 8 (1), 13/1-13/19CODEN: MBSEB6; ISSN:2077-0375. (MDPI AG)
    In this work, PVDF homopolymer was blended with PVDF-co-HFP copolymer and studied in terms of morphol., porosity, pore size, hydrophobicity, permeability, and mech. properties. Different solvents, namely N-methyl-2 pyrrolidone (NMP), THF, and DMF solvents, were used to fabricate blended PVDF flat sheet membranes without the introduction of any pore forming agent, through a non-solvent induced phase sepn. (NIPS) technique. Furthermore, the performance of the fabricated membranes was investigated for pressure and thermal driven applications. The porosity of the membranes was slightly increased with the increase in the overall content of PVDF and by the inclusion of PVDF copolymer. Total PVDF content, copolymer content, and mixed-solvent have a pos. effect on mech. properties. The addn. of copolymer increased the hydrophobicity when the total PVDF content was 20%. At 25% and with the inclusion of mixed-solvent, the hydrophobicity was adversely affected. The permeability of the membranes increased with the increase in the overall content of PVDF. Mixed-solvents significantly improved permeability.
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  40. 40
    Marino, T.; Galiano, F.; Simone, S.; Figoli, A. DMSO EVOL as novel non-toxic solvent for polyethersulfone membrane preparation. Environ. Sci. Pollut. Res. 2019, 26, 14774– 14785,  DOI: 10.1007/s11356-018-3575-9
    Google Scholar
    40
    DMSO EVOL as novel non-toxic solvent for polyethersulfone membrane preparation
    Marino, Tiziana; Galiano, Francesco; Simone, Silvia; Figoli, Alberto
    Environmental Science and Pollution Research (2019), 26 (15), 14774-14785CODEN: ESPLEC; ISSN:0944-1344. (Springer)
    The possibility of replacing traditional toxic solvents normally employed during the prepn. of polymeric membranes with greener alternatives represents a great challenge for safeguarding the human health and protecting the environment. In this work, an improved and pleasant-smelling version of dimethylsulfoxide , i.e., DMSO EVOL, was used as "greener solvent" for the prepn. of polyethersulfone microfiltration (MF) membranes using a combination of non-solvent and vapor-induced (NIPS and VIPS, resp.) phase sepn. technique for the first time. The effect of two different additives polyvinylpyrrolidone and poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic) together with polyethylene glycol on membrane properties and performances has been also evaluated. The membranes were characterized in terms of morphol., mech. resistance, pore size, and water permeability. The obtained results show that DMSO EVOL is able to replace 1-methyl-2-pyrrolidone (NMP), which is a more toxic solvent normally used for the prepn. of PES membranes. Furthermore, it was possible to tune the produced membranes in the range of MF (0.1-0.6 μm).
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  41. 41
    Wang, H. H.; Jung, J. T.; Kim, J. F.; Kim, S.; Drioli, E.; Lee, Y. M. A novel green solvent alternative for polymeric membrane preparation via nonsolvent-induced phase separation (NIPS). J. Membr. Sci. 2019, 574, 44– 54,  DOI: 10.1016/j.memsci.2018.12.051
    Google Scholar
    41
    A novel green solvent alternative for polymeric membrane preparation via nonsolvent-induced phase separation (NIPS)
    Wang, Ho Hyun; Jung, Jun Tae; Kim, Jeong F.; Kim, Seungju; Drioli, Enrico; Lee, Young Moo
    Journal of Membrane Science (2019), 574 (), 44-54CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    The membrane market has grown rapidly over the past several decades, supported by continuous improvements in membrane performance, module and process design, and fouling control. However, such growth will be unsustainable with current membrane fabrication methods that employ significant amts. of toxic solvents (e.g., N-methylpyrrolidone, dimethylacetamide, and DMF), thereby producing billions of liters of contaminated wastewater each year. A possible soln. is to identify greener alternatives with appropriate properties that are compatible with conventional polymers. The authors employed a novel green solvent, Rhodiasolv PolarClean, that is less toxic than current solvents and eco-friendly, while exhibiting the necessary properties to be employed as a solvent for membrane prepn. via the nonsolvent-induced phase sepn. (NIPS) method. Rhodiasolv PolarClean was successfully applied to membrane prepn. for H2O desalination and reclamation by ultrafiltration (UF) and nanofiltration (NF) with conventional polymers, including polysulfone (PSF), polyethersulfone (PES), and cellulose acetate (CA). The UF membranes prepd. from PES/Pluronic F127 and PSF/polyvinylpyrrolidone exhibited pure H2O permeabilities >314.5 ± 57.8 L m-2 h-1 bar-1 and tensile strength 3.78 ± 0.12 MPa with BSA rejection of 98.1 ± 0.4%. Cellulose acetate membrane used for NF applications demonstrated pure H2O permeability of 1.5 ± 0.25 L m-2 h-1 bar-1 with NaCl and MgCl2 rejection of 85.1 ± 5.7% and 93.2 ± 4.7%, resp. The performance of the prepd. membranes was competitive with current state-of-the-art membranes across all applications, indicating immediate applicability to improving the sustainability of membrane fabrication processes.
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  42. 42
    Arahman, N.; Mulyati, S.; Fahrina, A. Morphology and performance of pvdf membranes composed of triethylphospate and dimethyl sulfoxide solvents. Mater. Res. Express 2019, 6, 066419  DOI: 10.1088/2053-1591/ab1032
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    42
    Morphology and performance of pvdf membranes composed of triethylphospate and dimethyl sulfoxide solvents
    Arahman, Nasrul; Mulyati, Sri; Fahrina, Afrillia
    Materials Research Express (2019), 6 (6), 66419CODEN: MREAC3; ISSN:2053-1591. (IOP Publishing Ltd.)
    This study investigated the impact of different solvents on the characteristics and filtration performance of polyvinylidene fluoride (PVDF) membranes. PVDF membranes were fabricated via the non-solvent induced phase sepn. (NIPS) technique by dissolving 20% wt./wt. PVDF in tri-Et phosphate (TEP) and di-Me sulfoxide (DMSO), sep. The Hansen soly. parameter was studied as the kinetic aspect that influences membrane formation. The characteristics of the membranes were investigated including the membrane morphol. structure, surface roughness, chem. group compn., and tensile strength. The filtration performance of the resulting membranes was also conducted using cross-flow filtration including pure water permeability (PWP), synthetic CaCO3 suspension rejection, and membrane recovery after long-term filtration. The exptl. results showed that DMSO has a closer solvent affinity with the non-solvent resulting in a membrane with higher porosity than the TEP membrane with a denser structure. Furthermore, the PVDF/DMSO membrane also had higher PWP than the PVDF/TEP membrane. However, in terms of the filtration performance of the CaCO3 suspension, the PVDF/TEP membrane showed the best performance with higher flux permeation, better flux recovery of up to 96.6%, and the highest solute rejection reaching 100%. The anal. of the exptl. results are discussed further.
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  43. 43
    Evenepoel, N.; Wen, S.; Tsehaye, M. T.; Van der Bruggen, B. Van der Bruggen, B. Potential of DMSO as greener solvent for PES ultra- and nanofiltration membrane preparation. J. Appl. Polym. Sci. 2018, 135, 46494  DOI: 10.1002/app.46494
    Google Scholar
    There is no corresponding record for this reference.
  44. 44
    Xie, W.; Li, T.; Chen, C.; Wu, H.; Liang, S.; Chang, H.; Liu, B.; Drioli, E.; Wang, Q.; Crittenden, J. C. Using the Green Solvent Dimethyl Sulfoxide To Replace Traditional Solvents Partly and Fabricating PVC/PVC-g-PEGMA Blended Ultrafiltration Membranes with High Permeability and Rejection. Ind. Eng. Chem. Res. 2019, 58, 6413– 6423,  DOI: 10.1021/acs.iecr.9b00370
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    44
    Using the Green Solvent Dimethyl Sulfoxide To Replace Traditional Solvents Partly and Fabricating PVC/PVC-g-PEGMA Blended Ultrafiltration Membranes with High Permeability and Rejection
    Xie, Wancen; Li, Tong; Chen, Chen; Wu, Haibo; Liang, Songmiao; Chang, Haiqing; Liu, Baicang; Drioli, Enrico; Wang, Qingyuan; Crittenden, John C.
    Industrial & Engineering Chemistry Research (2019), 58 (16), 6413-6423CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
    Traditional solvents are harmful to human health and the environment. Here, we use a green solvent, DMSO, to replace traditional solvents partly as well as improve membrane performance. The amphiphilic copolymer poly(vinyl chloride)-graft-poly(ethylene glycol) Me ether methacrylate (PVC-g-PEGMA) is blended with PVC to improve the membrane performance. PVC cannot dissolve in DMSO, so based on the Hansen soly. parameter calcn., we investigated the mixt. solvents of traditional solvents and DMSO. We found that membranes fabricated by solvent 1-methyl-2-pyrrolidinone (NMP)/N,N-dimethylacetamide (DMAc)/DMSO = 4/3/3 had the highest pure water flux of 891.54 ± 64.41 L m-2 h-1 bar-1 and the highest sodium alginate (SA) rejection of 94.7 ± 1.3%. Other studies have rarely reported modified PVC membranes with such good performance. This membrane was a successful attempt to use a green solvent in membrane fabrication, meeting the challenges of sustainability in chem. enterprises.
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  45. 45
    Bottino, A.; Capannelli, G.; Munari, S.; Turturro, A. Solubility Parameters of Poly(vinylidene fluoride). J. Polym. Sci., Part B: Polym. Phys. 1988, 26, 785– 794,  DOI: 10.1002/polb.1988.090260405
    Google Scholar
    45
    Solubility parameters of poly(vinylidene fluoride)
    Bottino, A.; Capannelli, G.; Munari, S.; Turturro, A.
    Journal of Polymer Science, Part B: Polymer Physics (1988), 26 (4), 785-94CODEN: JPBPEM; ISSN:0887-6266.
    The soly. behavior of poly(vinylidene fluoride) in ∼50 liqs. was investigated. The results were input to a computer program to obtain a 3-dimensional representation of the polymer soly. region in the Hansen space; the values of dispersion, H bonding, and polar components of the total soly. parameter δt,p were evaluated. The latter was also estd. from limiting viscosity no. data in the solvents. Both exptl. methods gave δt,p values in very good agreement. Comparisons among these findings, the literature, and calcd. results are discussed.
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  46. 46
    Van Krevelen, D. W.; Te Nijenhuis, K. Cohesive Properties and Solubility. In Properties of Polymers, 4th ed.; Elsevier: Amsterdam, 2009; Chapter 7, pp 189– 227.
    Google Scholar
    There is no corresponding record for this reference.
  47. 47
    Liu, B.; Chen, C.; Zhang, W.; Crittenden, J.; Chen, Y. Low-cost antifouling PVC ultrafiltration membrane fabrication with Pluronic F 127: Effect of additives on properties and performance. Desalination 2012, 307, 26– 33,  DOI: 10.1016/j.desal.2012.07.036
    Google Scholar
    47
    Low-cost antifouling PVC ultrafiltration membrane fabrication with Pluronic F 127: Effect of additives on properties and performance
    Liu, Baicang; Chen, Chen; Zhang, Wen; Crittenden, John; Chen, Yongsheng
    Desalination (2012), 307 (), 26-33CODEN: DSLNAH; ISSN:0011-9164. (Elsevier B.V.)
    To fabricate low-cost hydrophilic and antifouling ultrafiltration membranes, in this work, we tuned the membrane surface hydrophilicity and porosity by adding different amts. of the amphiphilic copolymer (Pluronic F 127) into polyvinyl chloride (PVC) casting soln. The modified PVC membrane characteristics including oxygen content, morphol. and pore size, surface roughness, hydrophilicity, and permeability were characterized using XPS, SEM (SEM), at. force microscopy (AFM), contact angle measurement, and flux measurements. With the increase of Pluronic F 127 content from 0 to 10 wt.%, the oxygen content on the membrane surface increased and then reached an asymptote when 8 wt.% or greater Pluronic F 127 was used; the pore size and the pore d. both decreased; the membrane surface became more hydrophilic as indicated by the decreasing contact angles; and the flux declined by 30% when Pluronic F 127 reached 10 wt.%. Overall, the modified PVC membrane exhibited excellent antifouling feature even with Pluronic F 127 as low as 2 wt.%. Due to the membrane flux decline at 10 wt.% Pluronic F 127, the optimal addn. of Pluronic F 127 was 8 wt.%, which maintained the antifouling feature and high flux.
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  48. 48
    Asatekin, A.; Kang, S.; Elimelech, M.; Mayes, A. M. Anti-fouling ultrafiltration membranes containing polyacrylonitrile-graft-poly (ethylene oxide) comb copolymer additives. J. Membr. Sci. 2007, 298, 136– 146,  DOI: 10.1016/j.memsci.2007.04.011
    Google Scholar
    48
    Antifouling ultrafiltration membranes containing polyacrylonitrile-graft-poly(ethylene oxide) comb copolymer additives
    Asatekin, Ayse; Kang, Seoktae; Elimelech, Menachem; Mayes, Anne M.
    Journal of Membrane Science (2007), 298 (1+2), 136-146CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Membrane fouling is one of the most important challenges faced in membrane ultrafiltration (UF) operations. In this study, polyacrylonitrile-graft-poly(ethylene oxide) (PAN-g-PEO), an amphiphilic comb copolymer with a water-insol. polyacrylonitrile (PAN) backbone and hydrophilic poly(ethylene oxide) (PEO) side chains, was used as an additive in the manuf. of novel PAN UF membranes. During casting, the PAN-g-PEO additive segregates to form a PEO brush layer on all membrane surfaces, including internal pores. Wettability, pure water permeability, and resistance to irreversible fouling increased when either the amt. of PAN-g-PEO added to the membrane or the PEO content of the comb copolymer was increased. These trends were consistent with measured adhesion forces between the membranes and a carboxylated latex particle probe in an at. force microscopy (AFM) anal., and with the near-surface PEO coverage as detd. by XPS. SEM revealed further effects of additive incorporation on membrane morphol. In 24-h dead-end filtration studies, blend membranes prepd. with 20 wt.% PAN-g-PEO (comb PEO content: 39 wt.%) were found to resist irreversible fouling by 1000 ppm solns. of bovine serum albumin (BSA), sodium alginate, and humic acid, recovering the initial pure water flux completely by a pure water rinse, or a backwash in the case of humic acid. This exceptional anti-fouling performance holds promise for extending UF membrane lifetimes without need for aggressive cleaning procedures.
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  49. 49
    Zhao, X.; Su, Y.; Li, Y.; Zhang, R.; Zhao, J.; Jiang, Z. Engineering amphiphilic membrane surfaces based on PEO and PDMS segments for improved antifouling performances. J. Membr. Sci. 2014, 450, 111– 123,  DOI: 10.1016/j.memsci.2013.08.044
    Google Scholar
    49
    Engineering amphiphilic membrane surfaces based on PEO and PDMS segments for improved antifouling performances
    Zhao, Xueting; Su, Yanlei; Li, Yafei; Zhang, Runnan; Zhao, Jiaojiao; Jiang, Zhongyi
    Journal of Membrane Science (2014), 450 (), 111-123CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Antifouling membrane surfaces capable of reducing biofouling are highly desirable in a broad range of applications. In this study, amphiphilic membrane surfaces, derived from block copolymers bearing hydrophilic poly(ethylene oxide) (PEO) and low surface energy polydimethylsiloxane (PDMS) segments, have been constructed via surface segregation during the std. phase inversion process. The surface chem. features of the membranes are confirmed by contact angle measurement, XPS, Fourier transform IR (FTIR) and surface energy anal. The PEO segments are utilized to prevent biofoulant adsorption (fouling-resistance) whereas the PDMS segments are utilized to drive away the adsorbed biofoulants (fouling-release). The resultant surfaces exhibit better antifouling properties compared with the control polyethersulfone (PES) membrane when using bovine serum albumin (BSA), sodium alginate (SA) and yeast as three model biofoulants (proteins, polysaccharides and microorganisms). During the filtration of model biofoulant aq. solns., both irreversible and reversible flux declines are remarkably decreased and the flux recovery is retained completely after simple hydraulic washing. Static and dynamic biofoulants adsorption expts. reveal the synergistic effect of the PEO and PDMS segments on biofouling-resistance and biofouling-release. It is also found that the biofouling can be significantly reduced by the coexistence of optimized hydrophilic microdomains, low surface energy microdomains, and shear flow near membrane surfaces. Hopefully, the demonstrated attempt of membrane surface construction is favorable to prep. a wide spectrum of environmentally benign antifouling membranes.
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  50. 50
    Zhao, X.; Su, Y.; Chen, W.; Peng, J.; Jiang, Z. Grafting perfluoroalkyl groups onto polyacrylonitrile membrane surface for improved fouling release property. J. Membr. Sci. 2012, 415, 824– 834,  DOI: 10.1016/j.memsci.2012.05.075
    Google Scholar
    50
    Grafting perfluoroalkyl groups onto polyacrylonitrile membrane surface for improved fouling release property
    Zhao, Xueting; Su, Yanlei; Chen, Wenjuan; Peng, Jinming; Jiang, Zhongyi
    Journal of Membrane Science (2012), 415-416 (), 824-834CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    In this study, a novel kind of fluorinated polyacrylonitrile (PAN) membrane is prepd. by grafting perfluoroalkyl groups onto aminated PAN membrane surface through the acylation reaction. The surface compn. of the fluorinated PAN membranes is confirmed by Fourier transform IR spectroscopy (FT-IR) and XPS. The changes of membrane surface hydrophilicity, chem. heterogeneity and surface free energy after fluorination treatment are evaluated by contact angle measurement. When utilized for the ultrafiltration sepn. of oil/water emulsion, protein aq. soln. and polysaccharide aq. soln., the fluorinated PAN membranes exhibit superior fouling release properties, i.e., high flux recovery ratio (∼99%) and low total flux decline ratio (the minimal value is ∼13%). These results demonstrate the feasibility of grafting perfluoroalkyl groups onto the membrane surfaces to manipulate the physicochem. features and improve antifouling property. Moreover, the fluorinated PAN membranes acquire distinct reversible multi-responsive properties under ionic strength and pH stimuli.
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  51. 51
    Chen, Y. W.; Liu, D. M.; Deng, Q. L.; He, X. H.; Wang, X. F. Atom transfer radical polymerization directly from poly(vinylidene fluoride): Surface and antifouling properties. J. Polym. Sci., Part A: Polym. Chem. 2006, 44, 3434– 3443,  DOI: 10.1002/pola.21456
    Google Scholar
    51
    Atom transfer radical polymerization directly from poly(vinylidene fluoride): surface and antifouling properties
    Chen, Yiwang; Liu, Dongmei; Deng, Qilan; He, Xiaohui; Wang, Xiaofeng
    Journal of Polymer Science, Part A: Polymer Chemistry (2006), 44 (11), 3434-3443CODEN: JPACEC; ISSN:0887-624X. (John Wiley & Sons, Inc.)
    The direct prepn. of grafting polymer brushes from com. poly (vinylidene fluoride) (PVDF) films with surface-initiated atom transfer radical polymn. (ATRP) is demonstrated. The direct initiation of the secondary fluorinated site of PVDF facilitated grafting of the hydrophilic monomers from the PVDF surface. Homopolymer brushes of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and poly(ethylene glycol) monomethacrylate (PEGMA) were prepd. by ATRP from the PVDF surface. The chem. compn. and surface topog. of the graft-functionalized PVDF surfaces were characterized by XPS, attenuated total reflectance/Fourier transform IR spectroscopy, and at. force microscopy. A kinetic study revealed a linear increase in the graft concn. of poly[2-(N,N-dimethylamino)ethyl methacrylate] (PDMAEMA) and poly[poly(ethylene glycol) monomethacrylate] (PPEGMA) with the reaction time, indicating that the chain growth from the surface was consistent with a controlled or living process. The living chain ends were used as macroinitiators for the synthesis of diblock copolymer brushes. The water contact angles on PVDF films were reduced by the surface grafting of DMAEMA and PEGMA. Protein adsorption expts. revealed a substantial antifouling property of PPEGMA-grafted PVDF films and PDMAEMA-grafted PVDF films in comparison with the pristine PVDF surface.
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  52. 52
    Benz, M.; Euler, W. B. Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy. J. Appl. Polym. Sci. 2003, 89, 1093– 1100,  DOI: 10.1002/app.12267
    Google Scholar
    52
    Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy
    Benz, Marcel; Euler, William B.
    Journal of Applied Polymer Science (2003), 89 (4), 1093-1100CODEN: JAPNAB; ISSN:0021-8995. (John Wiley & Sons, Inc.)
    A method with good precision has been developed to quant. measure the degree of α-, β-, and γ crystallinity in poly(vinylidene fluoride) (PVDF) by means of IR spectroscopy. The phase compn. of soln.-deposited PVDF films was found to be strongly influenced by the presence of hydrophilic residues on the silicon substrate, the relative humidity present at film deposition, the spatial position on the substrate, and the thermal treatment of the deposited film. Films produced on pristine surfaces gave predominantly α-phase PVDF, but when a layer of polar solvent (acetone or methanol) remained on the surface, the films produced were predominantly γ phase. Higher humidity promoted a higher fraction of γ crystallinity in the soln.-deposited PVDF films. Soln.-cast films had highly variable compn. across the substrate, whereas spin-cast films were uniform. High-temp. annealing of PVDF films normally converts the polymer to the γ phase, but annealing the film while still attached to the silicon substrate inhibited this phase transformation. Low-temp. annealing of freestanding films led to a previously unreported thermal event in the DSC, a premelting process that is a kinetic event, assigned to a cryst. relaxation. Higher-temp. annealing gave a double endotherm, assigned to melting of different-sized cryst. domains.
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  53. 53
    Sencadas, V.; Gregorio, R.; Lanceros-Mendez, S. Processing and characterization of a novel nonporous poly(vinilidene fluoride) films in the beta phase. J. Non-Cryst. Solids 2006, 352, 2226– 2229,  DOI: 10.1016/j.jnoncrysol.2006.02.052
    Google Scholar
    53
    Processing and characterization of a novel nonporous polyvinylidene fluoride films in the β phase
    Sencadas, V.; Gregorio Filho, R.; Lanceros-Mendez, S.
    Journal of Non-Crystalline Solids (2006), 352 (21-22), 2226-2229CODEN: JNCSBJ; ISSN:0022-3093. (Elsevier B.V.)
    Poly(vinylidene fluoride) (PVDF) has remarkable properties leading to electro-optics, electro-mech. and biomedical applications. In particular, its piezo- and pyroelec. properties provide possibilities for many technol. applications. The semicryst. nature of PVDF, combined with the occurrence of at least four cryst. phases implies a complicated phys. microstructure. The most frequently described and important phase is the β phase. The piezo- and pyroelec. properties mainly depend on this phase, so increasing the β phase content has always been a great concern. It is possible to obtain films in the β phase by soln. but this material presents a high porosity leading to an opaque appearance and a decrease of the mech. and elec. properties. In this work, porous films in the β phase were obtained directly from the soln. at 60 °C. After applying pressure perpendicular to the surface of the film at elevated temp., the pores in the original sample are eliminated. The changes on the morphol. and crystallinity assocd. to the pressure treatment were also studied.
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  54. 54
    Gregorio, R. Determination of the alpha, beta, and gamma crystalline phases of poly(vinylidene fluoride) films prepared at different conditions. J. Appl. Polym. Sci. 2006, 100, 3272– 3279,  DOI: 10.1002/app.23137
    Google Scholar
    54
    Determination of the α, β, and γ crystalline phases of poly(vinylidene fluoride) films prepared at different conditions
    Gregorio, Rinaldo, Jr.
    Journal of Applied Polymer Science (2006), 100 (4), 3272-3279CODEN: JAPNAB; ISSN:0021-8995. (John Wiley & Sons, Inc.)
    Samples contg. the three cryst. phases of poly(vinylidene fluoride), α, β, and γ, were obtained under distinct crystn. conditions. Samples contg. exclusively unoriented β phase were obtained by crystn. from DMF soln. at 60°. Oriented β phase was obtained by uniaxial drawing, at 80°, of an originally α phase sample. Samples contg. exclusively α phase were obtained by melting and posterior cooling at room temp. Samples contg. both α and γ phases were obtained by melt crystn. at 164° for 16 and 36 h. Presence of the cryst. phases in each sample were confirmed by Fourier transform IR spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle x-ray scattering (WAXD), polarized light optical microscopy (PLOM), and SEM. IR absorption bands identifying unequivocally the presence of β and γ phases in a sample are presented. Soln. crystn. at T < 70° always results in the β phase, regardless of the solvent used. Melt temps. of the resp. phases were detd.
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  55. 55
    Chang, H.; Li, T.; Liu, B.; Chen, C.; He, Q.; Crittenden, J. C. Smart ultrafiltration membrane fouling control as desalination pretreatment of shale gas fracturing wastewater: The effects of backwash water. Environ. Int. 2019, 130, 104869,  DOI: 10.1016/j.envint.2019.05.063
    Google Scholar
    55
    Smart ultrafiltration membrane fouling control as desalination pretreatment of shale gas fracturing wastewater: The effects of backwash water
    Chang, Haiqing; Li, Tong; Liu, Baicang; Chen, Chen; He, Qiping; Crittenden, John C.
    Environment International (2019), 130 (), 104869CODEN: ENVIDV; ISSN:0160-4120. (Elsevier Ltd.)
    Increasing attention is being paid to the treatment of shale gas fracturing wastewater, including flowback and produced water (FPW). Energy-efficient pretreatment technologies suitable for desalinating and reusing FPW are of paramount importance. This work focused on enhanced fouling alleviation of ultrafiltration (UF) as a pretreatment for desalinating shale gas FPW in Sichuan Basin, China. The UF fouling behaviors under various backwash water sources or coagulant dosages were evaluated, and membrane surface characteristics were correlated with UF fouling. The feasibility of Fourier transform IR (FTIR) microscope mapping technique in quantifying UF fouling was also assessed. Various backwash water sources, including UF permeate, ultrapure water, nanofiltration (NF) permeate, reverse osmosis (RO) permeate, RO conc. and forward osmosis (FO) draw soln., were used to clean UF membranes fouled by shale gas FPW. The UF fouling behaviors were characterized by total and non-backwashable fouling rates. Membrane surface characteristics were analyzed by SEM (SEM), total tension surface and FTIR spectra. Protein-like substances in terms of fluorescence intensity in the backwash water decreased with the order of UF permeate, RO conc., NF permeate, RO permeate and FO draw soln. Compared with UF permeate backwashing, alleviated UF fouling was obsd. by using demineralized backwash water including ultrapure water and RO permeate, irresp. of hollow fiber and flat-sheet membranes. NF permeate and RO conc. after NF used as backwash water resulted in low and comparable membrane fouling with that in integrated coagulation-UF process under optimal dosage. Among the backwash water tested, FO draw soln. backwashing corresponded to the lowest UF fouling rates, which were even lower than that in the presence of coagulant under optimal dosage. The superiority of these backwash water sources to UF permeate was further confirmed by SEM images and FTIR spectra. The residual foulant mass on membrane surface and the total surface tension correlated well with non-backwashable and total fouling rates, resp. FTIR microscopy was a powerful surface mapping technique to characterize UF membrane fouling caused by shale gas FPW. Backwash water sources significantly influenced the fouling of UF membranes. In the integrated UF-NF-RO or UF-FO process, RO conc. or FO draw soln. were proposed as backwash water to enhance UF fouling control and decrease waste discharge simultaneously.
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  56. 56
    Shen, J.; Zhang, Q.; Yin, Q.; Cui, Z.; Li, W.; Xing, W. Fabrication and characterization of amphiphilic PVDF copolymer ultrafiltration membrane with high anti-fouling property. J. Membr. Sci. 2017, 521, 95– 103,  DOI: 10.1016/j.memsci.2016.09.006
    Google Scholar
    56
    Fabrication and characterization of amphiphilic PVDF copolymer ultrafiltration membrane with high anti-fouling property
    Shen, Jianliang; Zhang, Qi; Yin, Qiu; Cui, Zhaoliang; Li, Weixing; Xing, Weihong
    Journal of Membrane Science (2017), 521 (), 95-103CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Novel anti-fouling poly(vinylidene fluoride) (PVDF) membranes were fabricated via phase inversion method, directly using amphiphilic copolymers, which were synthesized from PVDFs with three different mol. wt. grafted poly(ethylene glycol) Me ether methacrylate (POEM) (PVDF-g-POEM), as membrane materials. Atom transfer radical polymn. (ATRP) method was employed to synthesize the amphiphilic PVDF copolymers. The membranes were characterized by SEM (SEM), pure water flux, contact angle measurement and BSA soln. filtration expts., etc. The permeability of the PVDF copolymer membrane reached to 567.8 L m-2 h-1 bar-1 with mol. wt. cut off (MWCO) of about 40.0 kDa. In addn., the stable state flux of the PVDF copolymer membranes was much higher than that of PVDF homopolymer membranes when BSA soln. was filtrated, and after cleaning, the pure water flux recovery ratio of the copolymer membrane reached to 98.1%. These results indicate that the prepd. PVDF membrane possesses good performance and anti-fouling property.
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  57. 57
    Vogler, E. A. Structure and reactivity of water at biomaterial surfaces. Adv. Colloid Interface Sci. 1998, 74, 69– 117,  DOI: 10.1016/S0001-8686(97)00040-7
    Google Scholar
    57
    Structure and reactivity of water at biomaterial surfaces
    Vogler, Erwin A.
    Advances in Colloid and Interface Science (1998), 74 (), 69-117CODEN: ACISB9; ISSN:0001-8686. (Elsevier Science B.V.)
    A review with 226 refs. The topics include mol. self-assocn., and role of water in biol. response to materials.
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  58. 58
    Tang, K.; Wang, X.; Yan, W.; Yu, J.; Xu, R. Fabrication of superhydrophilic Cu2O and CuO membranes. J. Membr. Sci. 2006, 286, 279– 284,  DOI: 10.1016/j.memsci.2006.10.005
    Google Scholar
    58
    Fabrication of superhydrophilic Cu2O and CuO membranes
    Tang, Kangjian; Wang, Xiaofang; Yan, Wenfu; Yu, Jihong; Xu, Ruren
    Journal of Membrane Science (2006), 286 (1+2), 279-284CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    The present work demonstrates a simple method on the direct prepn. of Cu2O and CuO membranes with super-hydrophilic property via calcination or redn. of the parent film of Cu(OH)2. By controlling the reaction conditions, Cu(OH)2 membranes with different surface patterns composed of nano-belts, whiskers, or stick-bundles were first prepd. Cu2O and CuO membranes were obtained from Cu(OH)2 membranes by subsequent redn. and dehydration, resp. The patterns of the parent film of Cu(OH)2 were maintained in the as-prepd. Cu2O and CuO membranes. Interestingly, the Cu(OH)2 crystals with various morphologies on the as-prepd. film were all transformed to close-packed Cu2O nanoparticles after the redn. Wettability investigation reveals that both Cu2O and CuO membranes have super-hydrophilic properties.
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  59. 59
    Yuan, J.; Liu, X.; Akbulut, O.; Hu, J.; Suib, S. L.; Kong, J.; Stellacci, F. Superwetting nanowire membranes for selective absorption. Nat. Nanotechnol. 2008, 3, 332– 336,  DOI: 10.1038/nnano.2008.136
    Google Scholar
    59
    Superwetting nanowire membranes for selective absorption
    Yuan, Jikang; Liu, Xiaogang; Akbulut, Ozge; Hu, Junqing; Suib, Steven L.; Kong, Jing; Stellacci, Francesco
    Nature Nanotechnology (2008), 3 (6), 332-336CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
    The construction of nanoporous membranes is of great technol. importance for various applications, including catalyst supports, filters for biomol. purifn., environmental remediation and seawater desalination. A major challenge is the scalable fabrication of membranes with the desirable combination of good thermal stability, high selectivity and excellent recyclability. Here the authors present a self-assembly method for constructing thermally stable, free-standing nanowire membranes that exhibit controlled wetting behavior ranging from superhydrophilic to superhydrophobic. These membranes can selectively absorb oils up to 20 times the material's wt. in preference to H2O, through a combination of superhydrophobicity and capillary action. Also, the nanowires that form the membrane structure can be re-suspended in solns. and subsequently re-form the original paper-like morphol. over many cycles. Results suggest an innovative material that should find practical applications in the removal of orgs., particularly in the field of oil spill cleanup. Through a combination of superhydrophobicity and capillary action, membranes made of Mn oxide nanowires can be used to selectively absorb hydrophobic contaminants, such as oil, from H2O.
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  60. 60
    Akthakul, A.; Salinaro, R. F.; Mayes, A. M. Antifouling polymer membranes with subnanometer size selectivity. Macromolecules 2004, 37, 7663– 7668,  DOI: 10.1021/ma048837s
    Google Scholar
    60
    Antifouling Polymer Membranes with Subnanometer Size Selectivity
    Akthakul, Ariya; Salinaro, Richard F.; Mayes, Anne M.
    Macromolecules (2004), 37 (20), 7663-7668CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    Membranes that deliver nanoscale size selectivity are desirable for applications ranging from water treatment to mol. sepns. Here we describe polymer thin film composite membranes coated with amphiphilic graft copolymers consisting of a poly(vinylidene fluoride) (PVDF) backbone and poly(oxyethylene methacrylate) (POEM) side chains, PVDF-g-POEM. Transmission electron microscopy and thermal anal. reveal that these materials molecularly self-assemble into bicontinuous nanophase domains of semicryst. PVDF, providing structural integrity, and poly(ethylene oxide) (PEO), providing selective transport channels of defined size. PVDF ultrafiltration membranes coated with PVDF-g-POEM wet instantaneously and reject >99.9% of emulsified oil from a 1000 ppm oleic acid/triethanolamine/water microemulsion feed at 66 psi without fouling. Their mol. sieving capability is demonstrated through sepn. of like-charged org. dyes varying in mol. dimensions by several angstroms. Thicker films of PVDF-g-POEM also act as a chromatograph, exhibiting time-dependent permeation of vitamins B2 and B12. Nonporous asym. membranes prepd. by immersion pptn. of PVDF/PVDF-g-POEM blend solns. exhibit sepn. capability similar to that of the thin film composites. These new nanochannel membranes hold potential utility for both high vol. and high end value liq.-based sepns.
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  61. 61
    Xu, Z.; Liao, J.; Tang, H.; Efome, J. E.; Li, N. Preparation and antifouling property improvement of Troger’s base polymer ultrafiltration membrane. J. Membr. Sci. 2018, 561, 59– 68,  DOI: 10.1016/j.memsci.2018.05.042
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    61
    Preparation and antifouling property improvement of Troger's base polymer ultrafiltration membrane
    Xu, Zhaozan; Liao, Jiayou; Tang, Hai; Efome, Johnson E.; Li, Nanwen
    Journal of Membrane Science (2018), 561 (), 59-68CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
    Troger's base (TB) polymers have received increasing interest for different potential applications in the field of membrane techniques. In this study, a TB polymer was used for the first time to prep. ultrafiltration (UF) membrane and its antifouling property was enhanced through membrane quaternization process. The pure water flux of TB UF membrane prepd. from NMP soln. was 448 L m-2 h-1 with a high rejection for solute (97% for bovine serum albumin (BSA) and 90% for humic acid). The high permeability of TB UF membrane was related to its high overall porosity, while the high sepn. property was attributed to its small av. pore size on the surface as evidenced by SEM observations. Due to the presence of tertiary amine groups, the TB membrane was further functionalized by the quaternization with Me iodide. Surprisingly, the antifouling property of quaternized TB (QTB)membrane was improved when using BSA as a model foulant when compared to the TB membrane. The flux recovery ratio of QTB membrane was enhanced from 55% to 91% when the quaternization degree was 10%. This may be attributed to the enhanced hydrophilicity of membrane surface after the quaternization of tertiary amino groups. More importantly,QTB membrane showed higher pure water flux, BSA soln. flux and flux recovery ratio than the com. PAN, PES, PSf and PVDF membranes through a three-cycle of membrane fouling test. Moreover, the effect of polymer concn. in the casting soln., type of solvent and coagulation bath temp. on the UF membrane morphol. and ultrafiltration performance were investigated.
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  • Abstract

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    Figure 1

    Figure 1. XPS spectra of the PVDF/PVDF-g-PEGMA membranes cast from different solvents or solvent mixtures: (a) PVDF1, DMSO; (b) PVDF2, DMSO/DMAc = 3:7; (c) PVDF3, DMSO/NMP = 5:5; and (d) PVDF4, DMSO/THF/DMF = 5:1.5:3.5. The content of the main elements was calculated and reported in the graphs.

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    Figure 2

    Figure 2. ATR-FTIR spectra of the PVDF/PVDF-g-PEGMA membranes cast using different solvents or solvent mixtures. PVDF1, DMSO; PVDF2, DMSO/DMAc = 3:7, PVDF3, DMSO/ NMP = 5:5; and PVDF4, DMSO/THF/DMF = 5:1.5:3.5. The 1727 cm−1 peak represents C═O bonds, and the 1638 cm−1 peak represents C═C bonds. Also indicated are the peaks relative to the characteristic bonds that represent the PVDF α and β crystalline phases.

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    Figure 3

    Figure 3. Representative SEM micrographs of the surface and cross-section morphologies of all of the PVDF/PVDF-g-PEGMA membranes. PVDF1, DMSO (A, B); PVDF2, DMSO/DMAc = 3:7 (C, D); PVDF3, NMP/DMSO = 5:5 (E, F); and PVDF4, THF/DMF/DMSO = 1.5:3.5:5 (G, H). The membrane surface images are shown in the top row, while the cross-sectional morphologies are shown in the bottom row.

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    Figure 4

    Figure 4. Contact angles as a function of time of PVDF/PVDF-g-PEGMA membranes using different solvents or solvent mixtures. PVDF1, DMSO; PVDF2, DMSO/DMAc = 7:3, PVDF3, DMSO/NMP = 5:5; and PVDF4, DMSO/THF/DMF = 5:1.5:3.5.

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    Figure 5

    Figure 5. Transport performance and fouling behavior of the PVDF/PVDF-g-PEGMA membranes using different solvents or solvent mixtures. PVDF1, DMSO; PVDF2, DMSO/DMAc=3:7; PVDF3, DMSO/NMP=5:5; and PVDF4, DMSO/THF/DMF=5:1.5:3.5. (A) Flux as a function of time using pure water or sodium alginate as feed solution; B) FRR, DRt, DRr, and DRir indices; and (C) SA rejection.

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  • References

    This article references 61 other publications.

    1. 1
      Buonomenna, M. G.; Lopez, L. C.; Favia, P.; d’Agostino, R.; Gordano, A.; Drioli, E. New PVDF membranes: The effect of plasma surface modification on retention in nanofiltration of aqueous solution containing organic compounds. Water Res. 2007, 41, 4309– 4316,  DOI: 10.1016/j.watres.2007.06.033
      1
      New PVDF membranes: The effect of plasma surface modification on retention in nanofiltration of aqueous solution containing organic compounds
      Buonomenna, M. G.; Lopez, L. C.; Favia, P.; d'Agostino, R.; Gordano, A.; Drioli, E.
      Water Research (2007), 41 (19), 4309-4316CODEN: WATRAG; ISSN:0043-1354. (Elsevier Ltd.)
      New nanofiltration membranes were prepd. by non-solvent-induced phase inversion from a PVDF/DMF/water system. The effect of exposure time before coagulation on the membrane characteristics (morphol., thickness, overall porosity, tensile strength) was studied. PVDF membrane prepd. at a fixed exposure time of 45 s (PF45) was further plasma surface modified (RF 13.56 MHz) (PF45psm), introducing amino groups on the membrane. The performances of PF45, PF45psm and of a com. nanofiltration membrane (N30F) were tested in the removal of 2 dyes from aq. soln., characterized by different charge and mol. wt. (congo red and methylene blue). The obsd. rejections depended more on the charge of the compd. than on their mol. wts. and results were optimized for the plasma modified membrane (PF45psm) with respect to unmodified (PF45) and com. N30F membranes. In particular, methylene blue was retained for 100% by PF45psm with a relative flux of 65% compared to 38% of rejection and 59% of relative flux obsd. for N30F.
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    2. 2
      Chen, Y.; Deng, Q.; Mao, J.; Nie, H.; Wu, L.; Zhou, W.; Huang, B. Controlled grafting from poly(vinylidene fluoride) microfiltration membranes via reverse atom transfer radical polymerization and antifouling properties. Polymer 2007, 48, 7604– 7613,  DOI: 10.1016/j.polymer.2007.10.043
      2
      Controlled grafting from poly(vinylidene fluoride) microfiltration membranes via reverse atom transfer radical polymerization and antifouling properties
      Chen, Yiwang; Deng, Qilan; Xiao, Jichun; Nie, Huarong; Wu, Lichuan; Zhou, Weihua; Huang, Biwu
      Polymer (2007), 48 (26), 7604-7613CODEN: POLMAG; ISSN:0032-3861. (Elsevier Ltd.)
      A reverse atom transfer radical polymn. (RATRP) with benzoyl peroxide (BPO)/CuCl/2,2-bipyridine (Bpy) was applied onto grafting of poly(Me methacrylate) (PMMA) and poly(polyethylene glycol Me ether methacrylate) (PPEGMA) from poly(vinylidene fluoride) (PVDF) microfiltration (MF) membrane surfaces, including the pore surfaces. The introduction of peroxide and hydroperoxide groups onto the PVDF membranes was achieved by UV irradn. in nitrogen, followed by air exposure. RATRP from UV pretreated hydrophobic PVDF membranes was then performed for attaching well-defined homopolymer. The chem. compn. of the modified PVDF membrane surfaces was characterized by attenuated total reflectance (ATR) FT-IR spectroscopy and XPS. The surface and cross-section morphol. of membranes were studied by SEM. The pore sizes of the pristine PVDF and the PMMA grafted PVDF membranes were measured using micro-image anal. and process software. With increase of graft concn., the pore size of the modified membranes decreased and became uniform. Kinetic studies of homogeneous (in toluene soln.) system revealed a linear increase in mol. wt. with the reaction time and narrow mol. wt. distribution, indicating that the chain growth from the membrane surface was a "controlled" or "living" grafting process. The introduction of the well-defined PMMA on the PVDF membrane gave rise to hydrophilicity. Protein adsorption and protein soln. permeation expts. revealed that the UV pretreated hydrophobic PVDF membrane subjected to surface-initiated RATRP of Me methacrylate (MMA) and polyethylene glycol Me ether methacrylate (PEGMA) exhibited good antifouling property.
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    3. 3
      Bonyadi, S.; Chung, T.-S. Highly porous and macrovoid-free PVDF hollow fiber membranes for membrane distillation by a solvent-dope solution co-extrusion approach. J. Membr. Sci. 2009, 331, 66– 74,  DOI: 10.1016/j.memsci.2009.01.014
      3
      Highly porous and macrovoid-free PVDF hollow fiber membranes for membrane distillation by a solvent-dope solution co-extrusion approach
      Bonyadi, Sina; Chung, Tai-Shung
      Journal of Membrane Science (2009), 331 (1+2), 66-74CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Highly porous and macrovoid-free PVDF hollow fiber membranes are of great interest for membrane contactor applications such as sea water desalination by membrane distn. in order to enhance the flux and long term stability of the process. For the first time in this paper, porous PVDF hollow fiber membranes with high outer surface porosity were fabricated by applying a two-phase flow consisting of a solvent and a dope soln. in the air-gap region of spinning through a non-solvent induced phase sepn. process (NIPS). In this approach, the dope soln. and the N-methylpyrrolidone (NMP) solvent were co-discharged from the middle and outer channels of a triple orifice spinneret, resp. Then, the two-phase flow went through an air-gap region and finally entered the coagulation bath. It was obsd. that the introduction of the two-phase flow greatly increased the outer surface porosity of the PVDF fibers and eliminated the formation of macrovoids in the cross-section of the fibers as well. It was also found that the energy efficiency and the flux of the fibers spun through the solvent-dope soln. co-extrusion were two to three times higher than the std. dry jet wet-spun fibers. A water vapor flux as high as 67 kg/(m2 h) at 80° was obtained through the newly spun fibers.
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    4. 4
      Boributh, S.; Chanachai, A.; Jiraratananon, R. Modification of PVDF membrane by chitosan solution for reducing protein fouling. J. Membr. Sci. 2009, 342, 97– 104,  DOI: 10.1016/j.memsci.2009.06.022
      4
      Modification of PVDF membrane by chitosan solution for reducing protein fouling
      Boributh, Somnuk; Chanachai, Ampai; Jiraratananon, Ratana
      Journal of Membrane Science (2009), 342 (1-2), 97-104CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      This work studied modification of hydrophobic membrane by chitosan soln. for the purpose of reducing protein fouling. The membrane used was flatsheet poly(vinylidene fluoride) (PVDF) of 0.22 μm pore size. The membranes were modified by 3 different methods, i.e., immersion method, flow through method and the combined flow through and surface flow method. Chitosan soln. concn. and modification time were varied. The modified membranes were then neutralized with NaOH soln. The results of SEM and Fourier transform IR spectroscopy (FTIR) study of modified membranes compared to unmodified membranes confirmed that there was chitosan coated on the membrane surfaces. The water contact angles and water fluxes decreased with increasing chitosan concn. and modification time. The result also indicated that modified membranes had higher hydrophilicity than unmodified membrane. In protein fouling expt., bovine serum albumin (BSA) was used as a protein model soln. Modified membranes exhibited good anti-fouling properties in reducing the irreversible membrane fouling. The membrane modified by a combined flow through and surface flow method showed the best anti-fouling properties compared with other methods. Protein adsorption on the modified membrane was highest at the isoelec. point (IEP) of BSA soln. and decreased as the soln. pH was far from the IEP.
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    5. 5
      Zheng, Z.-S.; Li, B.-B.; Duan, S.-Y.; Sun, D.; Peng, C.-K. Preparation of PVDF ultrafiltration membranes using PVA as pore surface hydrophilic modification agent with improved antifouling performance. Polym. Eng. Sci. 2019, 59, E384– E393,  DOI: 10.1002/pen.24996
      5
      Preparation of PVDF ultrafiltration membranes using PVA as pore surface hydrophilic modification agent with improved antifouling performance
      Zheng, Zhao-Shan; Li, Bing-Bing; Duan, Shi-Yuan; Sun, De; Peng, Cong-Kang
      Polymer Engineering & Science (2019), 59 (S1), E384-E393CODEN: PYESAZ; ISSN:0032-3888. (John Wiley & Sons, Inc.)
      Novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes were facilely fabricated using polyvinyl alc. (PVA) aq. soln. as the coagulation bath through phase inversion method. In the process, PVA was introduced into the pore surfaces of the PVDF membranes via the interdiffusion of the non-solvent water and the solvent. The effects of PVA content in the coagulation bath on membrane properties were systematically discussed. The results indicated that the increase of PVA content in coagulation bath resulted in the formations of the more sponge-like structures and the higher surface hydrophilicity. Smaller pore size led to lower water flux and higher bovine serum albumin rejection. Fouling resistance measurement indicated that the membranes made in PVA/water coagulation bath had higher flux recovery ratio (92.1%) than the membrane made in a pure water bath (71.0%). Furthermore, mech. property test revealed that the resulting membranes had high tensile strength and Young's modulus. In this work, we found that the morphol. and the property of the novel PVDF membranes could be detd. by the PVA content in the coagulation bath.
      >> More from SciFinder ®
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    6. 6
      Sun, D.; Yue, D.; Li, B.; Zheng, Z.; Meng, X. Preparation and performance of the novel PVDF ultrafiltration membranes blending with PVA modified SiO2 hydrophilic nanoparticles. Polym. Eng. Sci. 2019, 59, E412– E421,  DOI: 10.1002/pen.25002
      6
      Preparation and performance of the novel PVDF ultrafiltration membranes blending with PVA modified SiO2 hydrophilic nanoparticles
      Sun, De; Yue, Dongmin; Li, Bingbing; Zheng, Zhaoshan; Meng, Xiangchun
      Polymer Engineering & Science (2019), 59 (S1), E412-E421CODEN: PYESAZ; ISSN:0032-3888. (John Wiley & Sons, Inc.)
      In this study, PVA-SiO2 was synthesized by modifying silica (SiO2) with polyvinyl alc. (PVA), then a novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was prepd. by incorporating the prepd. PVA-SiO2 into membrane matrix using the non-solvent induced phase sepn. (NIPS) method. The effects of PVA-SiO2 particle on the properties of the PVDF membrane were systematically studied by scanning electron microscope (SEM), Fourier transform IR spectroscopy (FT-IR), surface pore size, porosity, and water contact angle. The results indicated that with the addn. of PVA-SiO2 particles in the PVDF UF membranes, membrane mean pore size increased from 80.06 to 126.00 nm, porosity improved from 77.4% to 89.1%, and water contact angle decreased from 75.61° to 63.10°. Furthermore, ultrafiltration expts. were conducted in terms of pure water flux, bovine serum albumin (BSA) rejection, and anti-fouling performance. It indicated that with the addn. of PVA-SiO2 particles, pure water flux increased from 70 to 126 L/m2 h, BSA rejection increased from 67% to 86%, flux recovery ratio increased from 60% to 96%, total fouling ratio decreased from 50% to 18.7%, and irreversible fouling ratio decreased from 40% to 4%. Membrane anti-fouling property was improved, and it can be expected that this work may provide some refs. to the improvement of the anti-fouling performance of the PVDF ultrafiltration membrane.
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    7. 7
      Benhabiles, O.; Galiano, F.; Marino, T.; Mahmoudi, H.; Lounici, H.; Figoli, A. Preparation and Characterization of TiO2-PVDF/PMMA Blend Membranes Using an Alternative Non-Toxic Solvent for UF/MF and Photocatalytic Application. Molecules 2019, 24, 724  DOI: 10.3390/molecules24040724
      7
      Preparation and characterization of TiO2-PVDF/PMMA blend membranes using an alternative non-toxic solvent for UF/MF and photocatalytic application
      Benhabiles, Ouassila; Galiano, Francesco; Marino, Tiziana; Mahmoudi, Hacene; Lounici, Hakim; Figoli, Alberto
      Molecules (2019), 24 (4), 724CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)
      The approach of the present work is based on the use of poly (methylmethacrylate) (PMMA) polymer, which is compatible with PVDF and TiO2 nanoparticles in casting solns., for the prepn. of nano-composites membranes using a safer and more compatible solvent. TiO2 embedded poly (vinylidene fluoride) (PVDF)/PMMA photocatalytic membranes were prepd. by phase inversion method. A non-solvent induced phase sepn. (NIPS) coupled with vapor induced phase sepn. (VIPS) was used to fabricate flat-sheet membranes using a dope soln. consisting of PMMA, PVDF, TiO2, and tri-Et phosphate (TEP) as an alternative non-toxic solvent. Membrane morphol. was examd. by SEM (SEM). Backscatter electron detector (BSD) mapping was used to monitor the inter-dispersion of TiO2 in the membrane surface and matrix. The effects of polymer concn., evapn. time, additives and catalyst amt. on the membrane morphol. and properties were investigated. Tests on photocatalytic degrdn. of methylene blue (MB) were also carried out using the membranes entrapped with different concns. of TiO2. The results of this study showed that nearly 99% MB removal can be easily achieved by photocatalysis using TiO2 immobilized on the membrane matrix. Moreover, it was obsd. that the quantity of TiO2 plays a significant role in the dye removal.
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    8. 8
      Wang, S.; Li, T.; Chen, C.; Chen, S.; Liu, B.; Crittenden, J. Non-woven PET fabric reinforced and enhanced the performance of ultrafiltration membranes composed of PVDF blended with PVDF-g-PEGMA for industrial applications. Appl. Surf. Sci. 2018, 435, 1072– 1079,  DOI: 10.1016/j.apsusc.2017.11.193
      8
      Non-woven PET fabric reinforced and enhanced the performance of ultrafiltration membranes composed of PVDF blended with PVDF-g-PEGMA for industrial applications
      Wang, Shuai; Li, Tong; Chen, Chen; Chen, Sheng; Liu, Baicang; Crittenden, John
      Applied Surface Science (2018), 435 (), 1072-1079CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
      Ultrafiltration (UF) membranes composed of poly(vinylidene fluoride) (PVDF) blended with poly(vinylidene fluoride)-graft-poly(ethylene glycol) Me ether methacrylate (PVDF-g-PEGMA) can present high flux and excellent foulant removal efficiencies under suitable prepn. conditions. However, these PVDF/PVDF-g-PEGMA blended membranes cannot be applied industrially because of the insufficient mech. strength (strength-to-break value of 8.4 ± 0.6 MPa). We incorporated two types of non-woven polyethylene terephthalate (PET) fabrics (thin hydrophobic and thick hydrophilic fabrics) as support layers to improve the mech. properties of the blended membranes. The thin and thick PET fabrics were able to significantly improve the tensile strength to 23.3 ± 3.7 MPa and 30.1 ± 1.4 MPa, resp. The PET fabrics had a limited impact on the sepn.-related membrane performance such as hydrophilicity, foulant rejection, whereas the mech. strength and pure water flux was improved several folds. The enhanced flux was attributed to the higher surface porosity and wider finger-like voids in the cross-section. The thin PET fabric with larger porosity was able to maintain a consistent toughness simultaneously; thus it is recommended as a support material for this blended membrane.
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    9. 9
      Venault, A.; Chang, C.-Y.; Tsai, T.-C.; Chang, H.-Y.; Bouyer, D.; Lee, K.-R.; Chang, Y. Surface zwitterionization of PVDF VIPS membranes for oil and water separation. J. Membr. Sci. 2018, 563, 54– 64,  DOI: 10.1016/j.memsci.2018.05.049
      9
      Surface zwitterionization of PVDF VIPS membranes for oil and water separation
      Venault, Antoine; Chang, Chia-Yu; Tsai, Tai-Chun; Chang, Hsiang-Yu; Bouyer, Denis; Lee, Kueir-Rarn; Chang, Yung
      Journal of Membrane Science (2018), 563 (), 54-64CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      This work aims at applying a combined polymn. and membrane surface-modification process, in order to hydrophilize poly(vinylidene fluoride) membranes prepd. by vapor-induced phase sepn. (VIPS), and eventually make them suitable for low transmembrane pressure (ΔP = 0.5bar) membrane sepn. of various oil-in-water (O/W) emulsions. Styrene and sulfobetaine monomers were mixed and allowed to react while the PVDF membrane was in contact with the reactive mixt., enabling self-assembling of the random polymer on the membrane as it was formed. Reaction parameters were optimized, and it was found that a solid content of 5wt%, a styrene/SBMA ratio of 40/60 and a reaction time of 5h led to very hydrophilic membrane (water contact angle: 12°). The combination of chem. analyses evidenced the successful and controlled surface modification process. Phys. analyses showed that deviating from the optimized conditions of styrene/SBMA ratio led to the formation of agglomerates (styrene-rich or SBMA-rich), assocd. to low porosity, and high coating d. The membranes were used to sep. emulsions of toluene/W, hexane/W, hexadecane/W, diesel/W and soybean oil/W, leading to sepn. efficiency of 99.0%, 99.2%, 99.1%, 99.0% and 99.0%, resp. This work thus presents a new avenue for surface modification of membrane with extremely efficient copolymers for which there is no common solvent, and brings several evidences of the suitability of VIPS membrane for cost-effective membrane sepn. of various emulsions.
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    10. 10
      Younas, H.; Bai, H.; Shao, J.; Han, Q.; Ling, Y.; He, Y. Super-hydrophilic and fouling resistant PVDF ultrafiltration membranes based on a facile prefabricated surface. J. Membr. Sci. 2017, 541, 529– 540,  DOI: 10.1016/j.memsci.2017.07.035
      10
      Super-hydrophilic and fouling resistant PVDF ultrafiltration membranes based on a facile prefabricated surface
      Younas, Hassan; Bai, Hongwei; Shao, Jiahui; Han, Qiaochu; Ling, Yuhan; He, Yiliang
      Journal of Membrane Science (2017), 541 (), 529-540CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      The hydrophilicity of PVDF membrane is playing an enormously important role in its widespread water treatment fields considering the excellent intrinsic properties of PVDF raw materials. Rather than the conventional surface modification or hybridization, herein, we report a novel approach to prep. super-hydrophilic PVDF ultrafiltration (UF) membrane by creating a prefabricated super-hydrophilic surface of inorg. TiO2 nanoparticles (NPs). The resultant membrane [prepd. by prefabrication surface adhesion of TiO2 NPs on PVDF-PEG-TiO2 hybrid membrane (SaT-PPT)] has a uniform distribution of TiO2 NPs not only on the membrane surface but also within membrane matrix, this will maximize the super-hydrophilic feature throughout the membrane: from inner porous structures to outer surfaces, and will avoid "dead-corner" to block fast water pass through. The performances of SaT-PPT membrane as compared with the control membranes (PVDF-PEG, and PVDF-PEG with TiO2 anchored only at surface) were investigated in terms of humic acid (HA) rejection, flux and flux decline in lab.-made cross flow UF expts. with and without UV irradn. It indicated that SaT-PPT membrane exhibited the highest hydrophilicity and flux, lowest flux decline and total resistance, but still with the highest HA rejection rate. In addn., SaT-PPT membrane showed the highest flux recovery after simple phys. cleaning to extend the longer life span of membrane. It is reasonable to believe that our developed SaT-PPT membranes will provide insightful engineering practices to benefit the broad water treatment applications.
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    11. 11
      Liu, C.; Wu, L.; Zhang, C.; Chen, W.; Luo, S. Surface hydrophilic modification of PVDF membranes by trace amounts of tannin and polyethyleneimine. Appl. Surf. Sci. 2018, 457, 695– 704,  DOI: 10.1016/j.apsusc.2018.06.131
      11
      Surface hydrophilic modification of PVDF membranes by trace amounts of tannin and polyethyleneimine
      Liu, Cong; Wu, Lili; Zhang, Chaocan; Chen, Wanyu; Luo, Shuo
      Applied Surface Science (2018), 457 (), 695-704CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
      A com. PVDF Microfiltration (MF) membrane was surface modified via a simple coating method for improvement of the hydrophilicity and anti-fouling performance. Herein, trace amts. of tannin acid (TA) and Polyethyleneimine (PEI) were firstly used with (3-Chloropropyl)trimethoxysilan (CTS) to endow the PVDF membranes with hydrophilicity. The physicochem. property of the modified membranes was characterized by SEM, AFM, ATR-FTIR and XPS resp., and a series of tests including water contact angle (WCA), underwater oil contact angle (OCA), pure water flux (PWF), anti-fouling expts. and so on were utilized to inspect the modified effect. Benefiting from the interactions among CTS, PEI and TA, several coating layers formed on the surface of the membranes and remarkable hydrophilicity with water contact angle of 16° was obtained, moreover, the pure water flux of this composite membranes could reach 10,782 L/M2·h.
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    12. 12
      Zeng, K.; Zhou, J.; Cui, Z.; Zhou, Y.; Shi, C.; Wang, X.; Zhou, L.; Ding, X.; Wang, Z.; Drioli, E. Insight into fouling behavior of poly(vinylidene fluoride) (PVDF) hollow fiber membranes caused by dextran with different pore size distributions. Chin. J. Chem. Eng. 2018, 26, 268– 277,  DOI: 10.1016/j.cjche.2017.04.008
      12
      Insight into fouling behavior of poly(vinylidene fluoride) (PVDF) hollow fiber membranes caused by dextran with different pore size distributions
      Zeng, Kailiang; Zhou, Jie; Cui, Zhaoliang; Zhou, Yue; Shi, Chuan; Wang, Xiaozu; Zhou, Liyue; Ding, Xiaobin; Wang, Zhaohui; Drioli, Enrico
      Chinese Journal of Chemical Engineering (2018), 26 (2), 268-277CODEN: CJCEEB; ISSN:1004-9541. (Chemical Industry Press)
      Membrane fouling is the key problem that occurs in membrane process for water treatment. However, how membrane microstructure influences the fouling behavior is still not clear. In this study, fouling behavior caused by dextran was deeply and systematically investigated by employing four poly(vinylidene fluoride) (PVDF) membranes with different pore sizes, ranging from 24 to 94 nm. The extent of fouling by dextran was accurately characterized by pore redn., flux decline, and the change of crit. flux. The result shows that membrane with the smallest pore size of 24 nm experienced the smallest fouling rate and the lowest fouling extent. As the membrane pore size increased, the crit. flux ranges were 105-114, 63-73, 38-44 and 34-43 L·m-2·h-1, resp. The crit. flux and fouling resistances indicated that the fouling propensity increases with the increase of membrane pore size. Two pilot membrane modules with mean pore size of 25 nm and 60 nm were applied in membrane filtration of surface water treatment. The results showed that serious irreversible membrane fouling occurred on the membrane with pore size of 60 nm at the permeate flux of 40.5 L·m-2·h-1. On the other hand, membrane with pore size of 25 nm exhibited much better anti-fouling performance when permeate flux was set to 40.5, 48 and 60 L·m-2·h-1.
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    13. 13
      Jayalakshmi, A.; Rajesh, S.; Mohan, D. Fouling propensity and separation efficiency of epoxidated polyethersulfone incorporated cellulose acetate ultrafiltration membrane in the retention of proteins. Appl. Surf. Sci. 2012, 258, 9770– 9781,  DOI: 10.1016/j.apsusc.2012.06.028
      13
      Fouling propensity and separation efficiency of epoxidated polyethersulfone incorporated cellulose acetate ultrafiltration membrane in the retention of proteins
      Jayalakshmi, A.; Rajesh, S.; Mohan, D.
      Applied Surface Science (2012), 258 (24), 9770-9781CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
      Epoxidated polyethersulfone (EPES) incorporated cellulose acetate (CA) ultrafiltration membranes were prepd. by diffusion induced pptn. technique in the absence and presence of pore former polyethyleneglycol-600. Effect of blend ratio on the compatibility, thermal stability, mech. strength, hydrophilicity, morphol., pure water flux, protein adsorption resistance, protein sepn. efficiency and fouling propensity of the CA/EPES blend membranes was evaluated. Addn. of EPES gave thin sepg. layer and spongy sub layer in CA/EPES blend membranes. The efficiency of these membranes in the sepn. of com. important proteins such as bovine serum albumin, egg albumin, pepsin and trypsin was studied and is enhanced as compared to CA membranes. The fouling-resistant capability of the membranes was studied by bovine serum albumin as the model foulant and flux recovery ratio of the membranes were calcd. Attempts have been made to correlate the changes in membrane morphol. with pure water flux, hydraulic resistance, thermal and mech. stability, sepn. efficiency and antifouling property of the CA/EPES membranes. The optimal combination of CA and EPES thus gave high performance UF membranes which are sufficiently dense to retain proteins and at the same time give economically viable fluxes.
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    14. 14
      Rajesh, S.; Jayalakshmi, A.; Senthilkumar, S.; Sankar, H. S. H.; Mohan, D. R. Performance Evaluation of Poly(amide-imide) Incorporated Cellulose Acetate Ultrafiltration Membranes in the Separation of Proteins and Its Fouling Propensity by AFM Imaging. Ind. Eng. Chem. Res. 2011, 50, 14016– 14029,  DOI: 10.1021/ie201181h
      14
      Performance Evaluation of Poly(amide-imide) Incorporated Cellulose Acetate Ultrafiltration Membranes in the Separation of Proteins and Its Fouling Propensity by AFM Imaging
      Rajesh, Sahadevan; Jayalakshmi, Ayyavoo; Senthilkumar, Sundararaj; Sankar, H. S. Hari; Mohan, Doraiswamy R.
      Industrial & Engineering Chemistry Research (2011), 50 (24), 14016-14029CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
      Polymeric membranes intended to be used in protein sepn. must be fouling resistant to reduce the interactions with proteins during operation. Therefore, cellulose acetate (CA) membranes with superior properties were prepd. by phase inversion technique using high-performance thermoplastic poly(amide-imide) (PAI) as the modification agent. The prepd. membranes were characterized using attenuated total reflectance Fourier transform IR spectroscopy (ATR-FTIR), SEM, at. force microscopy (AFM), mol. wt. cutoff, and pore size to investigate the influence of PAI on the properties of the resultant membranes. Intermol. interactions between the components in blend membranes were established by ATR-FTIR and SEM anal. showed that the blend CA membranes have thinner top layer and higher porosity in the sublayer. These prepd. membranes were subjected to the sepn. of proteins such as bovine serum albumin, egg albumin, pepsin, and trypsin. The fouling-resistant capability of the membranes was studied by bovine serum albumin as the model protein and increase in resistance during protein filtration was calcd. by resistance in series model anal. The fouled membranes were characterized by AFM imaging and these membranes were cleaned by washing with deionized water and subsequent sonication. From the AFM images of the fouled membranes it was clear that preferential adsorption takes place at specific locations on the membrane surface and is a function of surface roughness and membrane hydrophilicity. It is worth mentioning that the incorporation of poly(amide-imide) into the cellulose acetate matrix is an effective method for the development of low fouling ultrafiltration membranes for the sepn. of proteins.
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    15. 15
      Behboudi, A.; Jafarzadeh, Y.; Yegani, R. Polyvinyl chloride/polycarbonate blend ultrafiltration membranes for water treatment. J. Membr. Sci. 2017, 534, 18– 24,  DOI: 10.1016/j.memsci.2017.04.011
      15
      Polyvinyl chloride/polycarbonate blend ultrafiltration membranes for water treatment
      Behboudi, A.; Jafarzadeh, Y.; Yegani, R.
      Journal of Membrane Science (2017), 534 (), 18-24CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      In this study, PVC/PC blend membranes were prepd. via NIPS methods. Characterization techniques including FESEM, XRD, DSC, contact angle measurement, mech. properties, abrasion test, stability test, pure water flux and filtration of BSA soln. were applied to investigate the effects of PC content on the structure and performance of blend membranes. It was shown than PVC and PC are compatible and the results of FESEM, XRD and DSC analyses confirmed their compatibility. The pore size distribution of membranes shifted toward smaller pores as the content of PC in the membranes increased up to 50% and then shifted back toward larger pores. In addn., hydrophilicity, tensile strength and abrasion resistance of the blend membranes were improved. However, chem. stability of membranes against NaOH soln. after 10 days decreased by increasing PC content. Pure water flux and BSA rejection as the performance criteria of membranes improved due to the presence of PC. It was found that antifouling properties of membranes increased with increasing PC content. The results indicated that PVC/PC blend membranes were high performance and fouling resistant membranes in comparison with neat PVC membrane.
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    16. 16
      Ma, W.; Rajabzadeh, S.; Shaikh, A. R.; Kakihana, Y.; Sun, Y.; Matsuyama, H. Effect of type of poly(ethylene glycol) (PEG) based amphiphilic copolymer on antifouling properties of copolymer/poly(vinylidene fluoride) (PVDF) blend membranes. J. Membr. Sci. 2016, 514, 429– 439,  DOI: 10.1016/j.memsci.2016.05.021
      16
      Effect of type of poly(ethylene glycol) (PEG) based amphiphilic copolymer on antifouling properties of copolymer/poly(vinylidene fluoride) (PVDF) blend membranes
      Ma, Wenzhong; Rajabzadeh, Saeid; Shaikh, Abdul Rajjak; Kakihana, Yuriko; Sun, Yuchen; Matsuyama, Hideto
      Journal of Membrane Science (2016), 514 (), 429-439CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      The antifouling properties of poly(vinylidene fluoride) (PVDF) membranes were investigated by blending several types of synthesized amphiphilic poly(poly(ethylene glycol) Me ether methacrylate- Me methacrylate) [P(PEGMA- MMA)] copolymers with different initial PEGMA/MMA monomer ratios and PEG side chain lengths. Many types of membranes were prepd. using different copolymer/PVDF blend ratios via nonsolvent induced phase sepn. The membranes with similar pure water permeabilities and surface pore sizes were prepd. by controlling the dope soln. compn. Thus, the bovine serum albumin antifouling properties could be assessed under similar hydrodynamic filtration conditions. The membrane hydrophilicity, surface PEGMA coverage, and antifouling properties of the prepd. membranes increased with increasing copolymer/PVDF ratio and PEGMA/MMA monomer ratio of the copolymers and PEG length of the copolymer. A mol. dynamics simulation was performed to assess the surface chem. compn., and the results were compared with those of XPS. The antifouling properties depended more strongly on the membrane surface hydrophilicity when the copolymer chem. structures, i.e., the PEGMA/MMA monomer ratio and PEG side chain length, were changed, rather than when the copolymer/PVDF blend ratio was changed.
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    17. 17
      Hashim, N. A.; Liu, F.; Abed, M. R. M.; Li, K. Chemistry in spinning solutions: Surface modification of PVDF membranes during phase inversion. J. Membr. Sci. 2012, 415, 399– 411,  DOI: 10.1016/j.memsci.2012.05.024
      There is no corresponding record for this reference.
    18. 18
      Wu, H.; Li, T.; Liu, B.; Chen, C.; Wang, S.; Crittenden, J. C. Blended PVC/PVC-g-PEGMA ultrafiltration membranes with enhanced performance and antifouling properties. Appl. Surf. Sci. 2018, 455, 987– 996,  DOI: 10.1016/j.apsusc.2018.06.056
      18
      Blended PVC/PVC-g-PEGMA ultrafiltration membranes with enhanced performance and antifouling properties
      Wu, Haibo; Li, Tong; Liu, Baicang; Chen, Chen; Wang, Shuai; Crittenden, John C.
      Applied Surface Science (2018), 455 (), 987-996CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
      To improve the performance of poly(vinyl chloride) (PVC) membranes, we synthesized the amphiphilic copolymer PVC-graft-poly(ethylene glycol) Me ether methacrylate (PVC-g-PEGMA) via atom transfer radical polymn. (ATRP). We then fabricated PVC/PVC-g-PEGMA blended ultrafiltration membranes for the first time. The effect of the amt. of PVC-g-PEGMA from 5 to 20wt.% on the PVC membrane properties was systematically investigated. The successful synthesis of PVC-g-PEGMA was confirmed by the results of NMR (1H NMR), and Fourier transform IR spectroscopy (FTIR). With the increase in the amt. of the PVC-g-PEGMA additive from 0 to 20wt.%, we found that (1) the surface oxygen content of the membrane increased from 3.20% to 9.31%; (2) the membrane surface pore size and pore d. decreased; (3) the hydrophilicity and pure water flux of the membrane improved, but they plateaued, even slightly decreasing after the addn. of 15wt.% PVC-g-PEGMA; (4) the sodium alginate (SA) rejection ratios of all PVC/PVC-g-PEGMA blended membranes were higher than 90%; and (5) all blended PVC membranes exhibited higher flux recovery ratios (FRRs) than the pure PVC membrane; in particular, the FRR increased by 89% when 10wt.% PVC-g-PEGMA was added. These results indicated the enhanced antifouling properties of PVC/PVC-g-PEGMA blended ultrafiltration membranes.
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    19. 19
      Yang, B.; Yang, X.; Liu, B.; Chen, Z.; Chen, C.; Liang, S.; Chu, L.-Y.; Crittenden, J. PVDF blended PVDF-g-PMAA pH-responsive membrane: Effect of additives and solvents on membrane properties and performance. J. Membr. Sci. 2017, 541, 558– 566,  DOI: 10.1016/j.memsci.2017.07.045
      19
      PVDF blended PVDF-g-PMAA pH-responsive membrane: Effect of additives and solvents on membrane properties and performance
      Yang, Boxuan; Yang, Xin; Liu, Baicang; Chen, Zhiqiang; Chen, Chen; Liang, Songmiao; Chu, Liang-Yin; Crittenden, John
      Journal of Membrane Science (2017), 541 (), 558-566CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Poly(vinylidene fluoride) (PVDF) and its deriv. copolymer PVDF-graft-poly(methacrylic acid) (PVDF-g-PMAA) were blended to prep. pH-responsive membranes. The effects of the following factors on stimuli-responsive membrane performance were systematically examd.: (1) amt. of PVDF-g-PMAA additives, (2) extent of purifn., (3) concn. of polymer, (4) addn. of poly(ethylene glycol) (PEG), and (5) type of solvent. Field-emission SEM (FESEM), contact angle goniometry, at. force microscopy (AFM), attenuated total reflection Fourier transform IR (ATR-FTIR) spectroscopy, XPS, flux and solute rejection performance were used to characterize our fabricated membranes. We found that partially purified PVDF-g-PMAA membrane contains more surface PMAA than the purified one (purified signifies that excess unreacted species were removed). In addn., a much higher flux performance and pH-responsive coeff. were found for the partially purified PVDF-g-PMAA membranes; consequently, membranes were only partially purified throughout our work. The flux of the pH-responsive membranes is dramatically increased by decreasing the polymer concn. from 18 wt% to 15 wt% and by adding PEG and PVDF-g-PMAA. We could create a tunable broad range flux from ∼ 1 to 1200 L/m2 h by adjusting the polymer concn., adding PEG and PVDF-g-PMAA, and using different solvents. Our tunable approach has great potential for various applications (e.g., water treatment and food processing).
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    20. 20
      Hester, J. F.; Banerjee, P.; Won, Y. Y.; Akthakul, A.; Acar, M. H.; Mayes, A. M. ATRP of amphiphilic graft copolymers based on PVDF and their use as membrane additives. Macromolecules 2002, 35, 7652– 7661,  DOI: 10.1021/ma0122270
      20
      ATRP of Amphiphilic Graft Copolymers Based on PVDF and Their Use as Membrane Additives
      Hester, J. F.; Banerjee, P.; Won, Y.-Y.; Akthakul, A.; Acar, M. H.; Mayes, A. M.
      Macromolecules (2002), 35 (20), 7652-7661CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      The direct prepn. of amphiphilic graft copolymers from com. poly(vinylidene fluoride) (PVDF) using atom transfer radical polymn. (ATRP) is demonstrated. Here, direct initiation of the secondary fluorinated site of PVDF facilitates grafting of the hydrophilic comonomer. Amphiphilic comb copolymer derivs. of PVDF having poly(methacrylic acid) side chains (PVDF-g-PMAA) and poly(oxyethylene methacrylate) side chains (PVDF-g-POEM) are prepd. using this method. Surface segregation of PVDF-g-POEM additives in PVDF is examd. as a route to wettable, foul-resistant surfaces on PVDF filtration membranes. Because of surface segregation during the std. immersion pptn. process for membrane fabrication, a PVDF/5 wt. % PVDF-g-POEM membrane, having a bulk POEM concn. of 3.4 wt. %, exhibits a near-surface POEM concn. of 42 wt. % as measured by XPS. This membrane displays substantial resistance to BSA fouling compared with pure PVDF and wets spontaneously when placed in contact with water.
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    21. 21
      Ran, J.; Wu, L.; Zhang, Z.; Xu, T. Atom transfer radical polymerization (ATRP): A versatile and forceful tool for functional membranes. Prog. Polym. Sci. 2014, 39, 124– 144,  DOI: 10.1016/j.progpolymsci.2013.09.001
      21
      Atom transfer radical polymerization (ATRP): A versatile and forceful tool for functional membranes
      Ran, Jin; Wu, Liang; Zhang, Zhenghui; Xu, Tongwen
      Progress in Polymer Science (2014), 39 (1), 124-144CODEN: PRPSB8; ISSN:0079-6700. (Elsevier Ltd.)
      A review. The progress in atom transfer radical polymn. (ATRP) provides an effective means for the design and prepn. of functional membranes. Polymeric membranes with different macromol. architectures applied in fuel cells, including block and graft copolymers are conveniently prepd. via ATRP. Moreover, ATRP has also been widely used to introduce functionality onto the membrane surface to enhance its use in specific applications, such as antifouling, stimuli-responsive, adsorption function and pervaporation. In this review, the recent design and synthesis of advanced functional membranes via the ATRP technique are discussed in detail and their especial advantages are highlighted by selected examples ext. the principles for prepn. or modification of membranes using the ATRP methodol.
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    22. 22
      Xu, F. J.; Zhao, J. P.; Kang, E. T.; Neoh, K. G.; Li, J. Functionalization of nylon membranes via surface-initiated atom-transfer radical polymerization. Langmuir 2007, 23, 8585– 8592,  DOI: 10.1021/la7011342
      22
      Functionalization of Nylon Membranes via Surface-Initiated Atom-Transfer Radical Polymerization
      Xu, F. J.; Zhao, J. P.; Kang, E. T.; Neoh, K. G.; Li, J.
      Langmuir (2007), 23 (16), 8585-8592CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      The ability to manipulate and control the surface properties of nylons is of crucial importance to their widespread applications. In this work, surface-initiated atom-transfer radical polymn. (ATRP) is employed to tailor the functionality of the nylon membrane and pore surfaces in a well-controlled manner. A simple two-step method, involving the activation of surface amide groups with formaldehyde and the reaction of the resulting N-methylol polyamide with 2-bromoisobutyryl bromide, was first developed for the covalent immobilization of ATRP initiators on the nylon membrane and its pore surfaces. Functional polymer brushes of 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol)monomethacrylate (PEGMA) were prepd. via surface-initiated ATRP from the nylon membranes. A kinetics study revealed that the chain growth from the membranes was consistent with a "controlled" process. The dormant chain ends of the grafted HEMA polymer (P(HEMA)) and PEGMA polymer (P(PEGMA)) on the nylon membranes could be reactivated for the consecutive surface-initiated ATRP to produce the corresponding nylon membranes functionalized by P(HEMA)-b-P(PEGMA) and P(PEGMA)-b-P(HEMA) diblock copolymer brushes. In addn., membranes with grafted P(HEMA) and P(PEGMA) brushes exhibited good resistance to protein adsorption and fouling under continuous-flow conditions.
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    23. 23
      Zhou, Z.; Rajabzadeh, S.; Shaikh, A. R.; Kakihana, Y.; Ma, W.; Matsuyama, H. Effect of surface properties on antifouling performance of poly(vinyl chloride-co-poly(ethylene glycol)methyl ether methacrylate)/PVC blend membrane. J. Membr. Sci. 2016, 514, 537– 546,  DOI: 10.1016/j.memsci.2016.05.008
      23
      Effect of surface properties on antifouling performance of poly(vinyl chloride-co-poly(ethylene glycol)methyl ether methacrylate)/PVC blend membrane
      Zhou, Zhuang; Rajabzadeh, Saeid; Shaikh, Abdul Rajjak; Kakihana, Yuriko; Ma, Wenzhong; Matsuyama, Hideto
      Journal of Membrane Science (2016), 514 (), 537-546CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Several membranes with low fouling properties were prepd. by blending PVC with poly(vinyl chloride-co-poly(ethylene glycol) Me ether methacrylate) (poly(VC-co-PEGMA)) copolymer via a non-solvent induced phase sepn. (NIPS) method. Bovine serum albumin adsorption on polymer films decreased and the membrane surface pore sizes, hydrophilicities, and antifouling properties increased on increasing the poly(VC-co-PEGMA)/PVC blending ratio. Membrane surface PEGMA coverage increased on increasing the poly(VC-co-PEGMA)/PVC blending ratio, resulting in higher hydrophilicities and lower fouling propensities. Membranes with similar water permeabilities were prepd. by adjusting the dope soln. compn. to eliminate the effect of hydrodynamic conditions on membrane fouling performance. The effect of the membrane material on the membrane fouling propensity was much stronger than that of the membrane surface structure. Mol. dynamics simulations were performed to evaluate the surface chem. compn. of the membrane matrix and results were compared with results obtained from XPS measurements.
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    24. 24
      Matyjaszewski, K. Advanced Materials by Atom Transfer Radical Polymerization. Adv. Mater. 2018, 30, 1706441  DOI: 10.1002/adma.201706441
      There is no corresponding record for this reference.
    25. 25
      Matyjaszewski, K. Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives. Macromolecules 2012, 45, 4015– 4039,  DOI: 10.1021/ma3001719
      25
      Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives
      Matyjaszewski, Krzysztof
      Macromolecules (Washington, DC, United States) (2012), 45 (10), 4015-4039CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      A review. Current status and future perspectives in atom transfer radical polymn. (ATRP) are presented. Special emphasis is placed on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP. New hybrid materials based on org./inorg. systems and natural/synthetic polymers are presented. Some current and forthcoming applications are described.
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    26. 26
      Bhattacharya, A.; Misra, B. N. Grafting: a versatile means to modify polymers - Techniques, factors and applications. Prog. Polym. Sci. 2004, 29, 767– 814,  DOI: 10.1016/j.progpolymsci.2004.05.002
      26
      Grafting: a versatile means to modify polymers. Techniques, factors and applications
      Bhattacharya, A.; Misra, B. N.
      Progress in Polymer Science (2004), 29 (8), 767-814CODEN: PRPSB8; ISSN:0079-6700. (Elsevier B.V.)
      A review on graft copolymn. initiated by chem. treatment, photoirradn., high-energy radiation, and other means is given. Several prime controlling factors on grafting are discussed. Grafting is used in polymers for membrane sepn. and prodn. of conducting polymers.
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    27. 27
      Chang, Y.; Ko, C.-Y.; Shih, Y.-J.; Quemener, D.; Deratani, A.; Wei, T.-C.; Wang, D.-M.; Lai, J.-Y. Surface grafting control of PEGylated poly(vinylidene fluoride) antifouling membrane via surface-initiated radical graft copolymerization. J. Membr. Sci. 2009, 345, 160– 169,  DOI: 10.1016/j.memsci.2009.08.039
      27
      Surface grafting control of PEGylated poly(vinylidene fluoride) antifouling membrane via surface-initiated radical graft copolymerization
      Chang, Yung; Ko, Chao-Yin; Shih, Yu-Ju; Quemener, Damien; Deratani, Andre; Wei, Ta-Chin; Wang, Da-Ming; Lai, Juin-Yih
      Journal of Membrane Science (2009), 345 (1-2), 160-169CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      This work describes the surface grafting control of poly(vinylidene fluoride) (PVDF) membrane with poly(ethylene glycol) methacrylate (PEGMA) via three different modification approaches of surface-initiated radical graft copolymn., including thermal-induced radical polymn., surface-initiated atom transfer radical polymn. (ATRP), and low pressure plasma-induced graft-polymn. Two different surface grafting structures of PEGylated layer, brush-like PEGMA and network-like PEGMA, on PVDF membrane surface were achieved in this study. The chem. compn. and microstructure of the various surface-modified PEGylated PVDF membranes were characterized by Fourier transform IR spectroscopy (FT-IR), contact angle, at. force microscopy (AFM), and XPS measurements. Antifouling property of the modified PVDF membranes was evaluated according to the amt. of protein adsorption and the filtration test for BSA soln. in this study. Results show that the amt. of adsorbed proteins on the modified PVDF membranes not only depends on the surface hydrophilicity and hydration capacity but also assocs. with the surface grafting structures of PEGylated layers on PVDF membrane surface. This study not only introduces different practical modification approaches to achieve a hydrophobic PVDF membrane grafting hydrophilic PEGMA, but also provides a fundamental understanding of various PEGylated grafting structures governing the performance of antifouling properties.
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    28. 28
      Liu, B.; Chen, C.; Li, T.; Crittenden, J.; Chen, Y. High performance ultrafiltration membrane composed of PVDF blended with its derivative copolymer PVDF-g-PEGMA. J. Membr. Sci. 2013, 445, 66– 75,  DOI: 10.1016/j.memsci.2013.05.043
      28
      High performance ultrafiltration membrane composed of PVDF blended with its derivative copolymer PVDF-g-PEGMA
      Liu, Baicang; Chen, Chen; Li, Tong; Crittenden, John; Chen, Yongsheng
      Journal of Membrane Science (2013), 445 (), 66-75CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Amphiphilic graft copolymers were fabricated from a poly(vinylidene fluoride) (PVDF) backbone that was grafted with poly(ethylene glycol) Me ether methacrylate (PEGMA) (PVDF-g-PEGMA) using atom transfer radical polymn. (ATRP) method. An intriguing membrane of periodic pillar-like or sphere structures was formed using PVDF/PVDF-g-PEGMA block copolymer mixts. that were dissolved in suitable solvents. XPS, SEM, at. force microscopy (AFM), contact angle measurement, and flux performance tests were conducted to det. the membrane characteristics. The results show that the defect-free high performance ultrafiltration membrane can be fabricated by adding 10 wt% or 15 wt% PVDF-g-PEGMA to the PVDF backbone material using the phase inversion method. The permeate fluxes of the fabricated membrane with 10 wt% and 15 wt% PVDF534K-g-PEGMA are 5110 (L/m2 h bar) and 5170 (L/m2 h bar), resp., for deionized water under 0.07 MPa. The TOC (sodium alginate) removal efficiencies of PVDF membranes with 10 wt%, and 15 wt% PVDF534K-g-PEGMA are 90.97%, and 87.19%, resp. Furthermore, the removals of Suwannee River humic acid that contained 2 mM CaCl2 and 10 mM Ca(OH)2 for the PVDF membrane with 10 wt% PVDF534K-g-PEGMA are 72.11% and 77.69%, resp. This defect-free high-performance membranes show good potential for water treatment applications.
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    29. 29
      Hashim, N. A.; Liu, F.; Li, K. A simplified method for preparation of hydrophilic PVDF membranes from an amphiphilic graft copolymer. J. Membr. Sci. 2009, 345, 134– 141,  DOI: 10.1016/j.memsci.2009.08.032
      29
      A simplified method for preparation of hydrophilic PVDF membranes from an amphiphilic graft copolymer
      Hashim, N. Awanis; Liu, Fu; Li, K.
      Journal of Membrane Science (2009), 345 (1-2), 134-141CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      An attempt to reduce the no. of steps and hence the overall costs involved in the prepn. of hydrophilic flat sheet poly(vinylidene fluoride) (PVDF) membranes was made by adding PVDF polymer powders directly to an amphiphilic copolymer mixt. contg. PVDF grafted with poly(ethylene glycol) Me ether methacrylate (PEGMA) (PVDF-g-PEGMA), solvent and unreacted PEGMA from the atom transfer radical polymn. (ATRP) method. The membrane was characterized by Fourier transform infra-red attenuated reflection spectroscopy (FTIR-ATR), at. force microscopy (AFM), SEM and field emission SEM (FESEM), pure water flux, contact angle measurement and protein filtration expts. The presence of ester and ether groups attributable to the PEGMA in the resultant membrane was obsd. from FTIR-ATR spectra. From SEM and FESEM observations, an asym. membrane was formed with a thin skin layer accompanied by short finger-like and macrovoid structures, but the membrane morphol. changed when the copolymer content was increased. AFM reveals that the roughness of the membranes becomes greater with higher amt. of PVDF-g-PEGMA. The pure water permeation flux of the prepd. membrane increased significantly to 116 L/m2 h compared to pure PVDF membranes, while contact angle measurements show a moderate value of between 57° and 67°. The percentage of fouling recovered using water cleaning after protein filtration was found to be 100% for all membranes prepd. from this method. The results suggested that hydrophilic and low-fouling PVDF membranes were formed from the newly developed method. Since membrane hydrophilicity has a pronounced effect on the fouling properties, hydrophilic PVDF membranes developed from this process are anticipated to be suitable not only for bio-sepn., but also for wastewater treatment.
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    30. 30
      Chen, C.; Tang, L.; Liu, B.; Zhang, X.; Crittenden, J.; Chen, K. L.; Chen, Y. Forming mechanism study of unique pillar-like and defect-free PVDF ultrafiltration membranes with high flux. J. Membr. Sci. 2015, 487, 1– 11,  DOI: 10.1016/j.memsci.2015.03.075
      30
      Forming mechanism study of unique pillar-like and defect-free PVDF ultrafiltration membranes with high flux
      Chen, Chen; Tang, Li; Liu, Baicang; Zhang, Xiao; Crittenden, John; Chen, Kai Loon; Chen, Yongsheng
      Journal of Membrane Science (2015), 487 (), 1-11CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      An intriguing polyvinylidene fluoride (PVDF) membrane with unique pillar-like structures was synthesized. The membrane was synthesized using the phase inversion method by adding the amphiphilic graft copolymer PVDF grafted with poly(ethylene glycol) Me ether methacrylate (PEGMA) (PVDF-g-PEGMA) to the PVDF backbone material. It had high flux and high sodium alginate rejection ratio under low transmembrane pressure. However, the mechanisms for the formation of pillar-like structures are still unknown. In this paper, we explored the formation mechanism of pillar-like structures from aspects of solvent and additive. Based on the exptl. results and anal. of ternary diagram, both NMP and PVDF-g-PEGMA must coexist in casting soln. to form pillar-like structures. When NMP is in the solvent, PEGMA segments have enough time to migrate to the surface and repel each other during the phase inversion process. Finally, by using the target plot method, one membrane with the best performance was chosen as the proposed membrane from all membranes that casted under different conditions. The proposed membrane has a pure water flux of 2173 L/m2/h/bar. The total org. carbon (TOC, by sodium alginate) removal efficiency is 89%. This membrane may have a good potential in water treatment applications.
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    31. 31
      Wang, S.; Li, T.; Chen, C.; Liu, B.; Crittenden, J. C. PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times. Front. Environ. Sci. Eng. 2018, 12, 3,  DOI: 10.1007/s11783-017-0980-0
      There is no corresponding record for this reference.
    32. 32
      Sheldon, R. A. Metrics of Green Chemistry and Sustainability: Past, Present, and Future. ACS Sustainable Chem. Eng. 2018, 6, 32– 48,  DOI: 10.1021/acssuschemeng.7b03505
      32
      Metrics of Green Chemistry and Sustainability: Past, Present, and Future
      Sheldon, Roger A.
      ACS Sustainable Chemistry & Engineering (2018), 6 (1), 32-48CODEN: ASCECG; ISSN:2168-0485. (American Chemical Society)
      A review concerning historic, current, and future green chem. and sustainability metrics for fine org. chem. and pharmaceutical prodn. is given. Topics discussed include: green chem. origins; catalysis soln. to pollution; mass-based green metrics (atom economy and the E [environmental] factor, other mass-based metrics, system boundaries and intrinsic E factors); sustainability metrics and the environmental impact of wastes (energy efficiency metrics, environmental impact of wastes, life cycle assessment); from environmental impact to sustainability (circular economy); the bio-based economy; and summary and future outlook.
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    33. 33
      Giraud, R. J.; Williams, P. A.; Sehgal, A.; Ponnusamy, E.; Phillips, A. K.; Manley, J. B. Implementing Green Chemistry in Chemical Manufacturing: A Survey Report. ACS Sustainable Chem. Eng. 2014, 2, 2237– 2242,  DOI: 10.1021/sc500427d
      33
      Implementing Green Chemistry in Chemical Manufacturing: A Survey Report
      Giraud, Robert J.; Williams, Paul A.; Sehgal, Amit; Ponnusamy, Ettigounder; Phillips, Alan K.; Manley, Julie B.
      ACS Sustainable Chemistry & Engineering (2014), 2 (10), 2237-2242CODEN: ASCECG; ISSN:2168-0485. (American Chemical Society)
      A review. Green chem. is being implemented in chem. manufg. to advance sustainability. A scouting survey and recent industry-wide reports find that several green chem. principles and related metrics are routinely being implemented in the chem. manufg. sector. A cross-section of stakeholders surveyed agree that broader adoption of the principles of green chem. can be promoted by collaboration among companies to identify best practices and define opportunities to increase green chem. implementation in chem. manufg. Active collaborative efforts to improve implementation include identifying common attributes of effective process metrics, developing means of tracking sector-wide implementation, and defining industrial needs for translating promising green chem. ideas into implementable, cost-effective, and low business risk technologies.
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    34. 34
      Clarke, C. J.; Tu, W. C.; Levers, O.; Brohl, A.; Hallett, J. P. Green and Sustainable Solvents in Chemical Processes. Chem. Rev. 2018, 118, 747– 800,  DOI: 10.1021/acs.chemrev.7b00571
      34
      Green and Sustainable Solvents in Chemical Processes
      Clarke, Coby J.; Tu, Wei-Chien; Levers, Oliver; Brohl, Andreas; Hallett, Jason P.
      Chemical Reviews (Washington, DC, United States) (2018), 118 (2), 747-800CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review. Sustainable solvents are a topic of growing interest in both the research community and the chem. industry due to a growing awareness of the impact of solvents on pollution, energy usage and contributions to air quality and climate change. Solvent losses represent a major portion of org. pollution and solvent removal represents a large proportion of process energy consumption. To counter these emerging issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Much of the focus has been on the environmental credentials of the solvent itself, though how a substance is deployed is as important to sustainability as what it is made from. In this review we consider several aspects of the most prominent sustainable org. solvents in use today - ionic liqs., deep eutectic solvents, supercrit. fluids, switchable solvents, liq. polymers and renewable solvents. We examine not only the performance of each class of solvent within the context of the reactions or extns. for which it is employed, but also give consideration to the wider context of the process and system within which the solvent is deployed. A wide range of tech., economic and environmental factors are considered, giving a more complete picture of the current status of sustainable solvent research and development.
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    35. 35
      Sheldon, R. A. The E factor 25 years on: the rise of green chemistry and sustainability. Green Chem. 2017, 19, 18– 43,  DOI: 10.1039/C6GC02157C
      35
      The E factor 25 years on: the rise of green chemistry and sustainability
      Sheldon, Roger A.
      Green Chemistry (2017), 19 (1), 18-43CODEN: GRCHFJ; ISSN:1463-9262. (Royal Society of Chemistry)
      The global impact, over the last 25 years, of the principles of green chem. and sustainability, and the pivotal role of the E factor concept in driving resource efficiency and waste minimisation, in the chem. and allied industries, is reviewed. Following an introduction to the origins of green chem. and the E factor concept, the various metrics for measuring greenness are discussed. It is emphasized that mass-based metrics such as atom economy, E factors and process mass intensity (PMI) need to be supplemented by metrics, in particular life cycle assessment, which measure the environmental impact of waste and, in order to assess sustainability, by metrics which measure economic viability. The role of catalysis in waste minimisation is discussed and illustrated with examples of green catalytic processes such as aerobic oxidns. of alcs., catalytic C-C bond formation and olefin metathesis. Solvent losses are a major source of waste in the pharmaceutical and fine chem. industries and solvent redn. and replacement strategies, including the possible use of neoteric solvents, such as ionic liqs. and deep eutectic solvents, are reviewed. Biocatalysis has many benefits in the context of green and sustainable chem. and this is illustrated with recent examples in the synthesis of active pharmaceutical ingredients. The importance of the transition from an unsustainable economy based on fossil resources to a sustainable bio-based economy is delineated, as part of the overarching transition from an unsustainable linear economy to a truly green and sustainable circular economy based on resource efficiency and waste minimisation by design.
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    36. 36
      Gałuszka, A.; Migaszewski, Z.; Namiesnik, J. The 12 principles of green analytical chemistry and the SIGNIFICANCE mnemonic of green analytical practices. TrAC, Trends Anal. Chem. 2013, 50, 78– 84,  DOI: 10.1016/j.trac.2013.04.010
      36
      The 12 principles of green analytical chemistry and the SIGNIFICANCE mnemonic of green analytical practices
      Galuszka, Agnieszka; Migaszewski, Zdzislaw; Namiesnik, Jacek
      TrAC, Trends in Analytical Chemistry (2013), 50 (), 78-84CODEN: TTAEDJ; ISSN:0165-9936. (Elsevier B. V.)
      A review. The current rapid development of green anal. chem. (GAC) requires clear, concise guidelines in the form of GAC principles that will be helpful in greening lab. practices. The existing principles of green chem. and green engineering need revision for their use in GAC because they do not fully meet the needs of anal. chem. Tn this article a set of 12 principles is proposed consisting of known concepts (i.e. redn. in the use of reagents and energy, and elimination of waste, risk and hazard) together with some new ideas (i.e. the use of natural reagents), which will be important for the future of GAC.
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    37. 37
      Liu, F.; Hashim, N. A.; Liu, Y.; Abed, M. R. M.; Li, K. Progress in the production and modification of PVDF membranes. J. Membr. Sci. 2011, 375, 1– 27,  DOI: 10.1016/j.memsci.2011.03.014
      37
      Progress in the production and modification of PVDF membranes
      Liu, Fu; Hashim, N. Awanis; Liu, Yutie; Abed, M. R. Moghareh; Li, K.
      Journal of Membrane Science (2011), 375 (1-2), 1-27CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      A review. This article provides a comprehensive overview of recent progress in the prodn. and modification of poly(vinylidene fluoride) (PVDF) membranes for liq.-liq. or liq.-solid sepn. The cryst. properties, thermal stability and chem. resistance were firstly considered in this review, followed by the prodn. methods of PVDF membranes. Various modification approaches for PVDF membranes were subsequently reviewed. Finally, in the light of the anticipated role of PVDF as a superior membrane material, future prospects on the prodn. and modification of PVDF membranes were suggested.
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    38. 38
      Yeow, M. L.; Liu, Y. T.; Li, K. Morphological study of poly(vinylidene fluoride) asymmetric membranes: Effects of the solvent, additive, and dope temperature. J. Appl. Polym. Sci. 2004, 92, 1782– 1789,  DOI: 10.1002/app.20141
      38
      Morphological study of poly(vinylidene fluoride) asymmetric membranes: effects of the solvent, additive, and dope temperature
      Yeow, M. L.; Liu, Y. T.; Li, K.
      Journal of Applied Polymer Science (2004), 92 (3), 1782-1789CODEN: JAPNAB; ISSN:0021-8995. (John Wiley & Sons, Inc.)
      Asym. poly(vinylidene fluoride) (PVDF) membranes were cast with com.-grade Kynar K760 polymer pellets and four different solvent systems: N,N-dimethylacetamide (DMAc), N,N-dimethylformamide, 1-methyl-2-pyrrolidone, and tri-Et phosphate. With a focus on the PVDF/DMAc system, the effects of various additives (i.e., ethanol, glycerol, lithium chloride, lithium perchlorate, and water) on the resulting membrane morphol. were studied. The membrane morphol. was examd. with SEM. The effect of the dope soln. temp. on the membrane morphol. was also studied for the various additives used.
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    39. 39
      Ali, I.; Bamaga, O. A.; Gzara, L.; Bassyouni, M.; Abdel-Aziz, M. H.; Soliman, M. F.; Drioli, E.; Albeirutty, M. Assessment of Blend PVDF Membranes, and the Effect of Polymer Concentration and Blend Composition. Membranes 2018, 8, 13,  DOI: 10.3390/membranes8010013
      39
      Assessment of blend PVDF membranes, and the effect of polymer concentration and blend composition
      Ali, Imtiaz; Bamaga, Omar A.; Gzara, Lassaad; Bassyouni, M.; Abdel-Aziz, M. H.; Soliman, M. F.; Drioli, Enrico; Albeirutt, Mohammed
      Membranes (Basel, Switzerland) (2018), 8 (1), 13/1-13/19CODEN: MBSEB6; ISSN:2077-0375. (MDPI AG)
      In this work, PVDF homopolymer was blended with PVDF-co-HFP copolymer and studied in terms of morphol., porosity, pore size, hydrophobicity, permeability, and mech. properties. Different solvents, namely N-methyl-2 pyrrolidone (NMP), THF, and DMF solvents, were used to fabricate blended PVDF flat sheet membranes without the introduction of any pore forming agent, through a non-solvent induced phase sepn. (NIPS) technique. Furthermore, the performance of the fabricated membranes was investigated for pressure and thermal driven applications. The porosity of the membranes was slightly increased with the increase in the overall content of PVDF and by the inclusion of PVDF copolymer. Total PVDF content, copolymer content, and mixed-solvent have a pos. effect on mech. properties. The addn. of copolymer increased the hydrophobicity when the total PVDF content was 20%. At 25% and with the inclusion of mixed-solvent, the hydrophobicity was adversely affected. The permeability of the membranes increased with the increase in the overall content of PVDF. Mixed-solvents significantly improved permeability.
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    40. 40
      Marino, T.; Galiano, F.; Simone, S.; Figoli, A. DMSO EVOL as novel non-toxic solvent for polyethersulfone membrane preparation. Environ. Sci. Pollut. Res. 2019, 26, 14774– 14785,  DOI: 10.1007/s11356-018-3575-9
      40
      DMSO EVOL as novel non-toxic solvent for polyethersulfone membrane preparation
      Marino, Tiziana; Galiano, Francesco; Simone, Silvia; Figoli, Alberto
      Environmental Science and Pollution Research (2019), 26 (15), 14774-14785CODEN: ESPLEC; ISSN:0944-1344. (Springer)
      The possibility of replacing traditional toxic solvents normally employed during the prepn. of polymeric membranes with greener alternatives represents a great challenge for safeguarding the human health and protecting the environment. In this work, an improved and pleasant-smelling version of dimethylsulfoxide , i.e., DMSO EVOL, was used as "greener solvent" for the prepn. of polyethersulfone microfiltration (MF) membranes using a combination of non-solvent and vapor-induced (NIPS and VIPS, resp.) phase sepn. technique for the first time. The effect of two different additives polyvinylpyrrolidone and poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic) together with polyethylene glycol on membrane properties and performances has been also evaluated. The membranes were characterized in terms of morphol., mech. resistance, pore size, and water permeability. The obtained results show that DMSO EVOL is able to replace 1-methyl-2-pyrrolidone (NMP), which is a more toxic solvent normally used for the prepn. of PES membranes. Furthermore, it was possible to tune the produced membranes in the range of MF (0.1-0.6 μm).
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    41. 41
      Wang, H. H.; Jung, J. T.; Kim, J. F.; Kim, S.; Drioli, E.; Lee, Y. M. A novel green solvent alternative for polymeric membrane preparation via nonsolvent-induced phase separation (NIPS). J. Membr. Sci. 2019, 574, 44– 54,  DOI: 10.1016/j.memsci.2018.12.051
      41
      A novel green solvent alternative for polymeric membrane preparation via nonsolvent-induced phase separation (NIPS)
      Wang, Ho Hyun; Jung, Jun Tae; Kim, Jeong F.; Kim, Seungju; Drioli, Enrico; Lee, Young Moo
      Journal of Membrane Science (2019), 574 (), 44-54CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      The membrane market has grown rapidly over the past several decades, supported by continuous improvements in membrane performance, module and process design, and fouling control. However, such growth will be unsustainable with current membrane fabrication methods that employ significant amts. of toxic solvents (e.g., N-methylpyrrolidone, dimethylacetamide, and DMF), thereby producing billions of liters of contaminated wastewater each year. A possible soln. is to identify greener alternatives with appropriate properties that are compatible with conventional polymers. The authors employed a novel green solvent, Rhodiasolv PolarClean, that is less toxic than current solvents and eco-friendly, while exhibiting the necessary properties to be employed as a solvent for membrane prepn. via the nonsolvent-induced phase sepn. (NIPS) method. Rhodiasolv PolarClean was successfully applied to membrane prepn. for H2O desalination and reclamation by ultrafiltration (UF) and nanofiltration (NF) with conventional polymers, including polysulfone (PSF), polyethersulfone (PES), and cellulose acetate (CA). The UF membranes prepd. from PES/Pluronic F127 and PSF/polyvinylpyrrolidone exhibited pure H2O permeabilities >314.5 ± 57.8 L m-2 h-1 bar-1 and tensile strength 3.78 ± 0.12 MPa with BSA rejection of 98.1 ± 0.4%. Cellulose acetate membrane used for NF applications demonstrated pure H2O permeability of 1.5 ± 0.25 L m-2 h-1 bar-1 with NaCl and MgCl2 rejection of 85.1 ± 5.7% and 93.2 ± 4.7%, resp. The performance of the prepd. membranes was competitive with current state-of-the-art membranes across all applications, indicating immediate applicability to improving the sustainability of membrane fabrication processes.
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    42. 42
      Arahman, N.; Mulyati, S.; Fahrina, A. Morphology and performance of pvdf membranes composed of triethylphospate and dimethyl sulfoxide solvents. Mater. Res. Express 2019, 6, 066419  DOI: 10.1088/2053-1591/ab1032
      42
      Morphology and performance of pvdf membranes composed of triethylphospate and dimethyl sulfoxide solvents
      Arahman, Nasrul; Mulyati, Sri; Fahrina, Afrillia
      Materials Research Express (2019), 6 (6), 66419CODEN: MREAC3; ISSN:2053-1591. (IOP Publishing Ltd.)
      This study investigated the impact of different solvents on the characteristics and filtration performance of polyvinylidene fluoride (PVDF) membranes. PVDF membranes were fabricated via the non-solvent induced phase sepn. (NIPS) technique by dissolving 20% wt./wt. PVDF in tri-Et phosphate (TEP) and di-Me sulfoxide (DMSO), sep. The Hansen soly. parameter was studied as the kinetic aspect that influences membrane formation. The characteristics of the membranes were investigated including the membrane morphol. structure, surface roughness, chem. group compn., and tensile strength. The filtration performance of the resulting membranes was also conducted using cross-flow filtration including pure water permeability (PWP), synthetic CaCO3 suspension rejection, and membrane recovery after long-term filtration. The exptl. results showed that DMSO has a closer solvent affinity with the non-solvent resulting in a membrane with higher porosity than the TEP membrane with a denser structure. Furthermore, the PVDF/DMSO membrane also had higher PWP than the PVDF/TEP membrane. However, in terms of the filtration performance of the CaCO3 suspension, the PVDF/TEP membrane showed the best performance with higher flux permeation, better flux recovery of up to 96.6%, and the highest solute rejection reaching 100%. The anal. of the exptl. results are discussed further.
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    43. 43
      Evenepoel, N.; Wen, S.; Tsehaye, M. T.; Van der Bruggen, B. Van der Bruggen, B. Potential of DMSO as greener solvent for PES ultra- and nanofiltration membrane preparation. J. Appl. Polym. Sci. 2018, 135, 46494  DOI: 10.1002/app.46494
      There is no corresponding record for this reference.
    44. 44
      Xie, W.; Li, T.; Chen, C.; Wu, H.; Liang, S.; Chang, H.; Liu, B.; Drioli, E.; Wang, Q.; Crittenden, J. C. Using the Green Solvent Dimethyl Sulfoxide To Replace Traditional Solvents Partly and Fabricating PVC/PVC-g-PEGMA Blended Ultrafiltration Membranes with High Permeability and Rejection. Ind. Eng. Chem. Res. 2019, 58, 6413– 6423,  DOI: 10.1021/acs.iecr.9b00370
      44
      Using the Green Solvent Dimethyl Sulfoxide To Replace Traditional Solvents Partly and Fabricating PVC/PVC-g-PEGMA Blended Ultrafiltration Membranes with High Permeability and Rejection
      Xie, Wancen; Li, Tong; Chen, Chen; Wu, Haibo; Liang, Songmiao; Chang, Haiqing; Liu, Baicang; Drioli, Enrico; Wang, Qingyuan; Crittenden, John C.
      Industrial & Engineering Chemistry Research (2019), 58 (16), 6413-6423CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
      Traditional solvents are harmful to human health and the environment. Here, we use a green solvent, DMSO, to replace traditional solvents partly as well as improve membrane performance. The amphiphilic copolymer poly(vinyl chloride)-graft-poly(ethylene glycol) Me ether methacrylate (PVC-g-PEGMA) is blended with PVC to improve the membrane performance. PVC cannot dissolve in DMSO, so based on the Hansen soly. parameter calcn., we investigated the mixt. solvents of traditional solvents and DMSO. We found that membranes fabricated by solvent 1-methyl-2-pyrrolidinone (NMP)/N,N-dimethylacetamide (DMAc)/DMSO = 4/3/3 had the highest pure water flux of 891.54 ± 64.41 L m-2 h-1 bar-1 and the highest sodium alginate (SA) rejection of 94.7 ± 1.3%. Other studies have rarely reported modified PVC membranes with such good performance. This membrane was a successful attempt to use a green solvent in membrane fabrication, meeting the challenges of sustainability in chem. enterprises.
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    45. 45
      Bottino, A.; Capannelli, G.; Munari, S.; Turturro, A. Solubility Parameters of Poly(vinylidene fluoride). J. Polym. Sci., Part B: Polym. Phys. 1988, 26, 785– 794,  DOI: 10.1002/polb.1988.090260405
      45
      Solubility parameters of poly(vinylidene fluoride)
      Bottino, A.; Capannelli, G.; Munari, S.; Turturro, A.
      Journal of Polymer Science, Part B: Polymer Physics (1988), 26 (4), 785-94CODEN: JPBPEM; ISSN:0887-6266.
      The soly. behavior of poly(vinylidene fluoride) in ∼50 liqs. was investigated. The results were input to a computer program to obtain a 3-dimensional representation of the polymer soly. region in the Hansen space; the values of dispersion, H bonding, and polar components of the total soly. parameter δt,p were evaluated. The latter was also estd. from limiting viscosity no. data in the solvents. Both exptl. methods gave δt,p values in very good agreement. Comparisons among these findings, the literature, and calcd. results are discussed.
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    46. 46
      Van Krevelen, D. W.; Te Nijenhuis, K. Cohesive Properties and Solubility. In Properties of Polymers, 4th ed.; Elsevier: Amsterdam, 2009; Chapter 7, pp 189– 227.
      There is no corresponding record for this reference.
    47. 47
      Liu, B.; Chen, C.; Zhang, W.; Crittenden, J.; Chen, Y. Low-cost antifouling PVC ultrafiltration membrane fabrication with Pluronic F 127: Effect of additives on properties and performance. Desalination 2012, 307, 26– 33,  DOI: 10.1016/j.desal.2012.07.036
      47
      Low-cost antifouling PVC ultrafiltration membrane fabrication with Pluronic F 127: Effect of additives on properties and performance
      Liu, Baicang; Chen, Chen; Zhang, Wen; Crittenden, John; Chen, Yongsheng
      Desalination (2012), 307 (), 26-33CODEN: DSLNAH; ISSN:0011-9164. (Elsevier B.V.)
      To fabricate low-cost hydrophilic and antifouling ultrafiltration membranes, in this work, we tuned the membrane surface hydrophilicity and porosity by adding different amts. of the amphiphilic copolymer (Pluronic F 127) into polyvinyl chloride (PVC) casting soln. The modified PVC membrane characteristics including oxygen content, morphol. and pore size, surface roughness, hydrophilicity, and permeability were characterized using XPS, SEM (SEM), at. force microscopy (AFM), contact angle measurement, and flux measurements. With the increase of Pluronic F 127 content from 0 to 10 wt.%, the oxygen content on the membrane surface increased and then reached an asymptote when 8 wt.% or greater Pluronic F 127 was used; the pore size and the pore d. both decreased; the membrane surface became more hydrophilic as indicated by the decreasing contact angles; and the flux declined by 30% when Pluronic F 127 reached 10 wt.%. Overall, the modified PVC membrane exhibited excellent antifouling feature even with Pluronic F 127 as low as 2 wt.%. Due to the membrane flux decline at 10 wt.% Pluronic F 127, the optimal addn. of Pluronic F 127 was 8 wt.%, which maintained the antifouling feature and high flux.
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    48. 48
      Asatekin, A.; Kang, S.; Elimelech, M.; Mayes, A. M. Anti-fouling ultrafiltration membranes containing polyacrylonitrile-graft-poly (ethylene oxide) comb copolymer additives. J. Membr. Sci. 2007, 298, 136– 146,  DOI: 10.1016/j.memsci.2007.04.011
      48
      Antifouling ultrafiltration membranes containing polyacrylonitrile-graft-poly(ethylene oxide) comb copolymer additives
      Asatekin, Ayse; Kang, Seoktae; Elimelech, Menachem; Mayes, Anne M.
      Journal of Membrane Science (2007), 298 (1+2), 136-146CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Membrane fouling is one of the most important challenges faced in membrane ultrafiltration (UF) operations. In this study, polyacrylonitrile-graft-poly(ethylene oxide) (PAN-g-PEO), an amphiphilic comb copolymer with a water-insol. polyacrylonitrile (PAN) backbone and hydrophilic poly(ethylene oxide) (PEO) side chains, was used as an additive in the manuf. of novel PAN UF membranes. During casting, the PAN-g-PEO additive segregates to form a PEO brush layer on all membrane surfaces, including internal pores. Wettability, pure water permeability, and resistance to irreversible fouling increased when either the amt. of PAN-g-PEO added to the membrane or the PEO content of the comb copolymer was increased. These trends were consistent with measured adhesion forces between the membranes and a carboxylated latex particle probe in an at. force microscopy (AFM) anal., and with the near-surface PEO coverage as detd. by XPS. SEM revealed further effects of additive incorporation on membrane morphol. In 24-h dead-end filtration studies, blend membranes prepd. with 20 wt.% PAN-g-PEO (comb PEO content: 39 wt.%) were found to resist irreversible fouling by 1000 ppm solns. of bovine serum albumin (BSA), sodium alginate, and humic acid, recovering the initial pure water flux completely by a pure water rinse, or a backwash in the case of humic acid. This exceptional anti-fouling performance holds promise for extending UF membrane lifetimes without need for aggressive cleaning procedures.
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    49. 49
      Zhao, X.; Su, Y.; Li, Y.; Zhang, R.; Zhao, J.; Jiang, Z. Engineering amphiphilic membrane surfaces based on PEO and PDMS segments for improved antifouling performances. J. Membr. Sci. 2014, 450, 111– 123,  DOI: 10.1016/j.memsci.2013.08.044
      49
      Engineering amphiphilic membrane surfaces based on PEO and PDMS segments for improved antifouling performances
      Zhao, Xueting; Su, Yanlei; Li, Yafei; Zhang, Runnan; Zhao, Jiaojiao; Jiang, Zhongyi
      Journal of Membrane Science (2014), 450 (), 111-123CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Antifouling membrane surfaces capable of reducing biofouling are highly desirable in a broad range of applications. In this study, amphiphilic membrane surfaces, derived from block copolymers bearing hydrophilic poly(ethylene oxide) (PEO) and low surface energy polydimethylsiloxane (PDMS) segments, have been constructed via surface segregation during the std. phase inversion process. The surface chem. features of the membranes are confirmed by contact angle measurement, XPS, Fourier transform IR (FTIR) and surface energy anal. The PEO segments are utilized to prevent biofoulant adsorption (fouling-resistance) whereas the PDMS segments are utilized to drive away the adsorbed biofoulants (fouling-release). The resultant surfaces exhibit better antifouling properties compared with the control polyethersulfone (PES) membrane when using bovine serum albumin (BSA), sodium alginate (SA) and yeast as three model biofoulants (proteins, polysaccharides and microorganisms). During the filtration of model biofoulant aq. solns., both irreversible and reversible flux declines are remarkably decreased and the flux recovery is retained completely after simple hydraulic washing. Static and dynamic biofoulants adsorption expts. reveal the synergistic effect of the PEO and PDMS segments on biofouling-resistance and biofouling-release. It is also found that the biofouling can be significantly reduced by the coexistence of optimized hydrophilic microdomains, low surface energy microdomains, and shear flow near membrane surfaces. Hopefully, the demonstrated attempt of membrane surface construction is favorable to prep. a wide spectrum of environmentally benign antifouling membranes.
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    50. 50
      Zhao, X.; Su, Y.; Chen, W.; Peng, J.; Jiang, Z. Grafting perfluoroalkyl groups onto polyacrylonitrile membrane surface for improved fouling release property. J. Membr. Sci. 2012, 415, 824– 834,  DOI: 10.1016/j.memsci.2012.05.075
      50
      Grafting perfluoroalkyl groups onto polyacrylonitrile membrane surface for improved fouling release property
      Zhao, Xueting; Su, Yanlei; Chen, Wenjuan; Peng, Jinming; Jiang, Zhongyi
      Journal of Membrane Science (2012), 415-416 (), 824-834CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      In this study, a novel kind of fluorinated polyacrylonitrile (PAN) membrane is prepd. by grafting perfluoroalkyl groups onto aminated PAN membrane surface through the acylation reaction. The surface compn. of the fluorinated PAN membranes is confirmed by Fourier transform IR spectroscopy (FT-IR) and XPS. The changes of membrane surface hydrophilicity, chem. heterogeneity and surface free energy after fluorination treatment are evaluated by contact angle measurement. When utilized for the ultrafiltration sepn. of oil/water emulsion, protein aq. soln. and polysaccharide aq. soln., the fluorinated PAN membranes exhibit superior fouling release properties, i.e., high flux recovery ratio (∼99%) and low total flux decline ratio (the minimal value is ∼13%). These results demonstrate the feasibility of grafting perfluoroalkyl groups onto the membrane surfaces to manipulate the physicochem. features and improve antifouling property. Moreover, the fluorinated PAN membranes acquire distinct reversible multi-responsive properties under ionic strength and pH stimuli.
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    51. 51
      Chen, Y. W.; Liu, D. M.; Deng, Q. L.; He, X. H.; Wang, X. F. Atom transfer radical polymerization directly from poly(vinylidene fluoride): Surface and antifouling properties. J. Polym. Sci., Part A: Polym. Chem. 2006, 44, 3434– 3443,  DOI: 10.1002/pola.21456
      51
      Atom transfer radical polymerization directly from poly(vinylidene fluoride): surface and antifouling properties
      Chen, Yiwang; Liu, Dongmei; Deng, Qilan; He, Xiaohui; Wang, Xiaofeng
      Journal of Polymer Science, Part A: Polymer Chemistry (2006), 44 (11), 3434-3443CODEN: JPACEC; ISSN:0887-624X. (John Wiley & Sons, Inc.)
      The direct prepn. of grafting polymer brushes from com. poly (vinylidene fluoride) (PVDF) films with surface-initiated atom transfer radical polymn. (ATRP) is demonstrated. The direct initiation of the secondary fluorinated site of PVDF facilitated grafting of the hydrophilic monomers from the PVDF surface. Homopolymer brushes of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and poly(ethylene glycol) monomethacrylate (PEGMA) were prepd. by ATRP from the PVDF surface. The chem. compn. and surface topog. of the graft-functionalized PVDF surfaces were characterized by XPS, attenuated total reflectance/Fourier transform IR spectroscopy, and at. force microscopy. A kinetic study revealed a linear increase in the graft concn. of poly[2-(N,N-dimethylamino)ethyl methacrylate] (PDMAEMA) and poly[poly(ethylene glycol) monomethacrylate] (PPEGMA) with the reaction time, indicating that the chain growth from the surface was consistent with a controlled or living process. The living chain ends were used as macroinitiators for the synthesis of diblock copolymer brushes. The water contact angles on PVDF films were reduced by the surface grafting of DMAEMA and PEGMA. Protein adsorption expts. revealed a substantial antifouling property of PPEGMA-grafted PVDF films and PDMAEMA-grafted PVDF films in comparison with the pristine PVDF surface.
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    52. 52
      Benz, M.; Euler, W. B. Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy. J. Appl. Polym. Sci. 2003, 89, 1093– 1100,  DOI: 10.1002/app.12267
      52
      Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy
      Benz, Marcel; Euler, William B.
      Journal of Applied Polymer Science (2003), 89 (4), 1093-1100CODEN: JAPNAB; ISSN:0021-8995. (John Wiley & Sons, Inc.)
      A method with good precision has been developed to quant. measure the degree of α-, β-, and γ crystallinity in poly(vinylidene fluoride) (PVDF) by means of IR spectroscopy. The phase compn. of soln.-deposited PVDF films was found to be strongly influenced by the presence of hydrophilic residues on the silicon substrate, the relative humidity present at film deposition, the spatial position on the substrate, and the thermal treatment of the deposited film. Films produced on pristine surfaces gave predominantly α-phase PVDF, but when a layer of polar solvent (acetone or methanol) remained on the surface, the films produced were predominantly γ phase. Higher humidity promoted a higher fraction of γ crystallinity in the soln.-deposited PVDF films. Soln.-cast films had highly variable compn. across the substrate, whereas spin-cast films were uniform. High-temp. annealing of PVDF films normally converts the polymer to the γ phase, but annealing the film while still attached to the silicon substrate inhibited this phase transformation. Low-temp. annealing of freestanding films led to a previously unreported thermal event in the DSC, a premelting process that is a kinetic event, assigned to a cryst. relaxation. Higher-temp. annealing gave a double endotherm, assigned to melting of different-sized cryst. domains.
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    53. 53
      Sencadas, V.; Gregorio, R.; Lanceros-Mendez, S. Processing and characterization of a novel nonporous poly(vinilidene fluoride) films in the beta phase. J. Non-Cryst. Solids 2006, 352, 2226– 2229,  DOI: 10.1016/j.jnoncrysol.2006.02.052
      53
      Processing and characterization of a novel nonporous polyvinylidene fluoride films in the β phase
      Sencadas, V.; Gregorio Filho, R.; Lanceros-Mendez, S.
      Journal of Non-Crystalline Solids (2006), 352 (21-22), 2226-2229CODEN: JNCSBJ; ISSN:0022-3093. (Elsevier B.V.)
      Poly(vinylidene fluoride) (PVDF) has remarkable properties leading to electro-optics, electro-mech. and biomedical applications. In particular, its piezo- and pyroelec. properties provide possibilities for many technol. applications. The semicryst. nature of PVDF, combined with the occurrence of at least four cryst. phases implies a complicated phys. microstructure. The most frequently described and important phase is the β phase. The piezo- and pyroelec. properties mainly depend on this phase, so increasing the β phase content has always been a great concern. It is possible to obtain films in the β phase by soln. but this material presents a high porosity leading to an opaque appearance and a decrease of the mech. and elec. properties. In this work, porous films in the β phase were obtained directly from the soln. at 60 °C. After applying pressure perpendicular to the surface of the film at elevated temp., the pores in the original sample are eliminated. The changes on the morphol. and crystallinity assocd. to the pressure treatment were also studied.
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    54. 54
      Gregorio, R. Determination of the alpha, beta, and gamma crystalline phases of poly(vinylidene fluoride) films prepared at different conditions. J. Appl. Polym. Sci. 2006, 100, 3272– 3279,  DOI: 10.1002/app.23137
      54
      Determination of the α, β, and γ crystalline phases of poly(vinylidene fluoride) films prepared at different conditions
      Gregorio, Rinaldo, Jr.
      Journal of Applied Polymer Science (2006), 100 (4), 3272-3279CODEN: JAPNAB; ISSN:0021-8995. (John Wiley & Sons, Inc.)
      Samples contg. the three cryst. phases of poly(vinylidene fluoride), α, β, and γ, were obtained under distinct crystn. conditions. Samples contg. exclusively unoriented β phase were obtained by crystn. from DMF soln. at 60°. Oriented β phase was obtained by uniaxial drawing, at 80°, of an originally α phase sample. Samples contg. exclusively α phase were obtained by melting and posterior cooling at room temp. Samples contg. both α and γ phases were obtained by melt crystn. at 164° for 16 and 36 h. Presence of the cryst. phases in each sample were confirmed by Fourier transform IR spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle x-ray scattering (WAXD), polarized light optical microscopy (PLOM), and SEM. IR absorption bands identifying unequivocally the presence of β and γ phases in a sample are presented. Soln. crystn. at T < 70° always results in the β phase, regardless of the solvent used. Melt temps. of the resp. phases were detd.
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    55. 55
      Chang, H.; Li, T.; Liu, B.; Chen, C.; He, Q.; Crittenden, J. C. Smart ultrafiltration membrane fouling control as desalination pretreatment of shale gas fracturing wastewater: The effects of backwash water. Environ. Int. 2019, 130, 104869,  DOI: 10.1016/j.envint.2019.05.063
      55
      Smart ultrafiltration membrane fouling control as desalination pretreatment of shale gas fracturing wastewater: The effects of backwash water
      Chang, Haiqing; Li, Tong; Liu, Baicang; Chen, Chen; He, Qiping; Crittenden, John C.
      Environment International (2019), 130 (), 104869CODEN: ENVIDV; ISSN:0160-4120. (Elsevier Ltd.)
      Increasing attention is being paid to the treatment of shale gas fracturing wastewater, including flowback and produced water (FPW). Energy-efficient pretreatment technologies suitable for desalinating and reusing FPW are of paramount importance. This work focused on enhanced fouling alleviation of ultrafiltration (UF) as a pretreatment for desalinating shale gas FPW in Sichuan Basin, China. The UF fouling behaviors under various backwash water sources or coagulant dosages were evaluated, and membrane surface characteristics were correlated with UF fouling. The feasibility of Fourier transform IR (FTIR) microscope mapping technique in quantifying UF fouling was also assessed. Various backwash water sources, including UF permeate, ultrapure water, nanofiltration (NF) permeate, reverse osmosis (RO) permeate, RO conc. and forward osmosis (FO) draw soln., were used to clean UF membranes fouled by shale gas FPW. The UF fouling behaviors were characterized by total and non-backwashable fouling rates. Membrane surface characteristics were analyzed by SEM (SEM), total tension surface and FTIR spectra. Protein-like substances in terms of fluorescence intensity in the backwash water decreased with the order of UF permeate, RO conc., NF permeate, RO permeate and FO draw soln. Compared with UF permeate backwashing, alleviated UF fouling was obsd. by using demineralized backwash water including ultrapure water and RO permeate, irresp. of hollow fiber and flat-sheet membranes. NF permeate and RO conc. after NF used as backwash water resulted in low and comparable membrane fouling with that in integrated coagulation-UF process under optimal dosage. Among the backwash water tested, FO draw soln. backwashing corresponded to the lowest UF fouling rates, which were even lower than that in the presence of coagulant under optimal dosage. The superiority of these backwash water sources to UF permeate was further confirmed by SEM images and FTIR spectra. The residual foulant mass on membrane surface and the total surface tension correlated well with non-backwashable and total fouling rates, resp. FTIR microscopy was a powerful surface mapping technique to characterize UF membrane fouling caused by shale gas FPW. Backwash water sources significantly influenced the fouling of UF membranes. In the integrated UF-NF-RO or UF-FO process, RO conc. or FO draw soln. were proposed as backwash water to enhance UF fouling control and decrease waste discharge simultaneously.
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    56. 56
      Shen, J.; Zhang, Q.; Yin, Q.; Cui, Z.; Li, W.; Xing, W. Fabrication and characterization of amphiphilic PVDF copolymer ultrafiltration membrane with high anti-fouling property. J. Membr. Sci. 2017, 521, 95– 103,  DOI: 10.1016/j.memsci.2016.09.006
      56
      Fabrication and characterization of amphiphilic PVDF copolymer ultrafiltration membrane with high anti-fouling property
      Shen, Jianliang; Zhang, Qi; Yin, Qiu; Cui, Zhaoliang; Li, Weixing; Xing, Weihong
      Journal of Membrane Science (2017), 521 (), 95-103CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Novel anti-fouling poly(vinylidene fluoride) (PVDF) membranes were fabricated via phase inversion method, directly using amphiphilic copolymers, which were synthesized from PVDFs with three different mol. wt. grafted poly(ethylene glycol) Me ether methacrylate (POEM) (PVDF-g-POEM), as membrane materials. Atom transfer radical polymn. (ATRP) method was employed to synthesize the amphiphilic PVDF copolymers. The membranes were characterized by SEM (SEM), pure water flux, contact angle measurement and BSA soln. filtration expts., etc. The permeability of the PVDF copolymer membrane reached to 567.8 L m-2 h-1 bar-1 with mol. wt. cut off (MWCO) of about 40.0 kDa. In addn., the stable state flux of the PVDF copolymer membranes was much higher than that of PVDF homopolymer membranes when BSA soln. was filtrated, and after cleaning, the pure water flux recovery ratio of the copolymer membrane reached to 98.1%. These results indicate that the prepd. PVDF membrane possesses good performance and anti-fouling property.
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    57. 57
      Vogler, E. A. Structure and reactivity of water at biomaterial surfaces. Adv. Colloid Interface Sci. 1998, 74, 69– 117,  DOI: 10.1016/S0001-8686(97)00040-7
      57
      Structure and reactivity of water at biomaterial surfaces
      Vogler, Erwin A.
      Advances in Colloid and Interface Science (1998), 74 (), 69-117CODEN: ACISB9; ISSN:0001-8686. (Elsevier Science B.V.)
      A review with 226 refs. The topics include mol. self-assocn., and role of water in biol. response to materials.
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    58. 58
      Tang, K.; Wang, X.; Yan, W.; Yu, J.; Xu, R. Fabrication of superhydrophilic Cu2O and CuO membranes. J. Membr. Sci. 2006, 286, 279– 284,  DOI: 10.1016/j.memsci.2006.10.005
      58
      Fabrication of superhydrophilic Cu2O and CuO membranes
      Tang, Kangjian; Wang, Xiaofang; Yan, Wenfu; Yu, Jihong; Xu, Ruren
      Journal of Membrane Science (2006), 286 (1+2), 279-284CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      The present work demonstrates a simple method on the direct prepn. of Cu2O and CuO membranes with super-hydrophilic property via calcination or redn. of the parent film of Cu(OH)2. By controlling the reaction conditions, Cu(OH)2 membranes with different surface patterns composed of nano-belts, whiskers, or stick-bundles were first prepd. Cu2O and CuO membranes were obtained from Cu(OH)2 membranes by subsequent redn. and dehydration, resp. The patterns of the parent film of Cu(OH)2 were maintained in the as-prepd. Cu2O and CuO membranes. Interestingly, the Cu(OH)2 crystals with various morphologies on the as-prepd. film were all transformed to close-packed Cu2O nanoparticles after the redn. Wettability investigation reveals that both Cu2O and CuO membranes have super-hydrophilic properties.
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    59. 59
      Yuan, J.; Liu, X.; Akbulut, O.; Hu, J.; Suib, S. L.; Kong, J.; Stellacci, F. Superwetting nanowire membranes for selective absorption. Nat. Nanotechnol. 2008, 3, 332– 336,  DOI: 10.1038/nnano.2008.136
      59
      Superwetting nanowire membranes for selective absorption
      Yuan, Jikang; Liu, Xiaogang; Akbulut, Ozge; Hu, Junqing; Suib, Steven L.; Kong, Jing; Stellacci, Francesco
      Nature Nanotechnology (2008), 3 (6), 332-336CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
      The construction of nanoporous membranes is of great technol. importance for various applications, including catalyst supports, filters for biomol. purifn., environmental remediation and seawater desalination. A major challenge is the scalable fabrication of membranes with the desirable combination of good thermal stability, high selectivity and excellent recyclability. Here the authors present a self-assembly method for constructing thermally stable, free-standing nanowire membranes that exhibit controlled wetting behavior ranging from superhydrophilic to superhydrophobic. These membranes can selectively absorb oils up to 20 times the material's wt. in preference to H2O, through a combination of superhydrophobicity and capillary action. Also, the nanowires that form the membrane structure can be re-suspended in solns. and subsequently re-form the original paper-like morphol. over many cycles. Results suggest an innovative material that should find practical applications in the removal of orgs., particularly in the field of oil spill cleanup. Through a combination of superhydrophobicity and capillary action, membranes made of Mn oxide nanowires can be used to selectively absorb hydrophobic contaminants, such as oil, from H2O.
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    60. 60
      Akthakul, A.; Salinaro, R. F.; Mayes, A. M. Antifouling polymer membranes with subnanometer size selectivity. Macromolecules 2004, 37, 7663– 7668,  DOI: 10.1021/ma048837s
      60
      Antifouling Polymer Membranes with Subnanometer Size Selectivity
      Akthakul, Ariya; Salinaro, Richard F.; Mayes, Anne M.
      Macromolecules (2004), 37 (20), 7663-7668CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      Membranes that deliver nanoscale size selectivity are desirable for applications ranging from water treatment to mol. sepns. Here we describe polymer thin film composite membranes coated with amphiphilic graft copolymers consisting of a poly(vinylidene fluoride) (PVDF) backbone and poly(oxyethylene methacrylate) (POEM) side chains, PVDF-g-POEM. Transmission electron microscopy and thermal anal. reveal that these materials molecularly self-assemble into bicontinuous nanophase domains of semicryst. PVDF, providing structural integrity, and poly(ethylene oxide) (PEO), providing selective transport channels of defined size. PVDF ultrafiltration membranes coated with PVDF-g-POEM wet instantaneously and reject >99.9% of emulsified oil from a 1000 ppm oleic acid/triethanolamine/water microemulsion feed at 66 psi without fouling. Their mol. sieving capability is demonstrated through sepn. of like-charged org. dyes varying in mol. dimensions by several angstroms. Thicker films of PVDF-g-POEM also act as a chromatograph, exhibiting time-dependent permeation of vitamins B2 and B12. Nonporous asym. membranes prepd. by immersion pptn. of PVDF/PVDF-g-POEM blend solns. exhibit sepn. capability similar to that of the thin film composites. These new nanochannel membranes hold potential utility for both high vol. and high end value liq.-based sepns.
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    61. 61
      Xu, Z.; Liao, J.; Tang, H.; Efome, J. E.; Li, N. Preparation and antifouling property improvement of Troger’s base polymer ultrafiltration membrane. J. Membr. Sci. 2018, 561, 59– 68,  DOI: 10.1016/j.memsci.2018.05.042
      61
      Preparation and antifouling property improvement of Troger's base polymer ultrafiltration membrane
      Xu, Zhaozan; Liao, Jiayou; Tang, Hai; Efome, Johnson E.; Li, Nanwen
      Journal of Membrane Science (2018), 561 (), 59-68CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)
      Troger's base (TB) polymers have received increasing interest for different potential applications in the field of membrane techniques. In this study, a TB polymer was used for the first time to prep. ultrafiltration (UF) membrane and its antifouling property was enhanced through membrane quaternization process. The pure water flux of TB UF membrane prepd. from NMP soln. was 448 L m-2 h-1 with a high rejection for solute (97% for bovine serum albumin (BSA) and 90% for humic acid). The high permeability of TB UF membrane was related to its high overall porosity, while the high sepn. property was attributed to its small av. pore size on the surface as evidenced by SEM observations. Due to the presence of tertiary amine groups, the TB membrane was further functionalized by the quaternization with Me iodide. Surprisingly, the antifouling property of quaternized TB (QTB)membrane was improved when using BSA as a model foulant when compared to the TB membrane. The flux recovery ratio of QTB membrane was enhanced from 55% to 91% when the quaternization degree was 10%. This may be attributed to the enhanced hydrophilicity of membrane surface after the quaternization of tertiary amino groups. More importantly,QTB membrane showed higher pure water flux, BSA soln. flux and flux recovery ratio than the com. PAN, PES, PSf and PVDF membranes through a three-cycle of membrane fouling test. Moreover, the effect of polymer concn. in the casting soln., type of solvent and coagulation bath temp. on the UF membrane morphol. and ultrafiltration performance were investigated.
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    Supporting Information

    The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsomega.9b02674.

    • Calculations and experiment results; AFM morphologies of the fabricated membranes; mechanical performances of the fabricated membranes; calculation process using a group contribution method to calculate the solubility parameter of PEGMA; δd, δh, and δp values and densities of some solvents; detailed calculation of the δd, δh, and δp values of mixed solvents; FRR, DRt, DRr; and DRir results of the fabricated membranes (PDF)


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