Synthesis and Polyelectrolyte Functionalization of Hollow Fiber Membranes Formed by Solvent Transfer Induced Phase SeparationClick to copy article linkArticle link copied!
- Henrik Siegel*Henrik Siegel*Email: [email protected]Van’t Hoff Laboratory of Physical and Colloid Chemistry, Department of Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CH Utrecht, The NetherlandsMore by Henrik Siegel
- Alessio J. SprockelAlessio J. SprockelVan’t Hoff Laboratory of Physical and Colloid Chemistry, Department of Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CH Utrecht, The NetherlandsMore by Alessio J. Sprockel
- Matthew S. SchwengerMatthew S. SchwengerHenry M. Rowan College of Engineering, Rowan University, Glassboro, New Jersey 08028, United StatesMore by Matthew S. Schwenger
- Jesse M. SteenhoffJesse M. SteenhoffVan’t Hoff Laboratory of Physical and Colloid Chemistry, Department of Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CH Utrecht, The NetherlandsMore by Jesse M. Steenhoff
- Iske AchterhuisIske AchterhuisFaculty of Science and Technology, Membrane Surface Science, Membrane Science and Technology, MESA+ Institute of Nanotechnology, University of Twente, 7500 AE Enschede, The NetherlandsMore by Iske Achterhuis
- Wiebe M. de VosWiebe M. de VosFaculty of Science and Technology, Membrane Surface Science, Membrane Science and Technology, MESA+ Institute of Nanotechnology, University of Twente, 7500 AE Enschede, The NetherlandsMore by Wiebe M. de Vos
- Martin F. Haase*Martin F. Haase*Email: [email protected]Van’t Hoff Laboratory of Physical and Colloid Chemistry, Department of Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CH Utrecht, The NetherlandsMore by Martin F. Haase
Abstract
Ultrafiltration membranes are important porous materials to produce freshwater in an increasingly water-scarce world. A recent approach to generate porous membranes is solvent transfer induced phase separation (STrIPS). During STrIPS, the interplay of liquid–liquid phase separation and nanoparticle self-assembly results in hollow fibers with small surface pores, ideal structures for applications as filtration membranes. However, the underlying mechanisms of the membrane formation are still poorly understood, limiting the control over structure and properties. To address this knowledge gap, we study the nonequilibrium dynamics of hollow fiber structure evolution. Confocal microscopy reveals the distribution of nanoparticles and monomers during STrIPS. Diffusion simulations are combined with measurements of the interfacial elasticity to investigate the effect of the solvent concentration on nanoparticle stabilization. Furthermore, we demonstrate the separation performance of the membrane during ultrafiltration. To this end, polyelectrolyte multilayers are deposited on the membrane, leading to tunable pores that enable the removal of dextran molecules of different molecular weights (>360 kDa, >60 kDa, >18 kDa) from a feed water stream. The resulting understanding of STrIPS and the simplicity of the synthesis process open avenues to design novel membranes for advanced separation applications.
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License Summary*
You are free to share(copy and redistribute) this article in any medium or format and to adapt(remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
*Disclaimer
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License Summary*
You are free to share(copy and redistribute) this article in any medium or format and to adapt(remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
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1. Introduction
2. Results and Discussion
2.1. Structure Control via STrIPS
2.2. Structure Formation Mechanisms
2.3. Membrane Separations with STrIPS Hollow Fibers
3. Conclusions
4. Experimental Section
4.1. Hollow Fiber Precursor Preparation
4.2. Fiber Preparation via STrIPS
4.3. Structure Characterization
4.4. Transient Solvent Diffusion Modeling
4.5. Pendant Drop Experiments
4.6. ζ-Potential Measurements
4.7. Polyelectrolyte Multilayer Coating
4.8. Hollow Fiber Performance Testing
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsami.2c10343.
Pendant drop shrinkage with nanoparticles (SI Video 1) (MP4)
Pendant drop shrinkage without nanoparticles (SI Video 2) (MP4)
Measurement of ternary phase diagrams; fiber precursor dispersion preparation; microfluidic device assembly; microfluidic fiber spinning; fluorescence emission spectra of Rhodamine 110 chloride and Nile red; transient solvent diffusion modeling; pendant drop experiments; droplet shape analysis; methanol as solvent for STrIPS; STrIPS fibers with Ludox nanoparticle dispersions at different pH; fiber internal surface area analysis; surface pore size distribution of STrIPS hollow fiber membrane; PSS/CTA+ complexation; polyelectrolyte functionalization of STrIPS hollow fibers; and STrIPS hollow fiber testing module; membrane separations with STrIPS hollow fibers (PDF)
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Acknowledgments
This publication is part of the project “Bijel templated membranes for molecular separations” (with project number 18632 of the research programme Vidi 2019), which is financed by the Dutch Research Council (NWO). A.J. Sprockel was supported by funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement no. 802636).
References
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- 7Feng, C. Y.; Khulbe, K. C.; Matsuura, T.; Ismail, A. F. Recent Progresses in Polymeric Hollow Fiber Membrane Preparation, Characterization and Applications. Sep. Purif. Technol. 2013, 111, 43– 71, DOI: 10.1016/J.SEPPUR.2013.03.017Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmsFCltLk%253D&md5=11398ec9dee5a88271742eadb7a4a9b5Recent progresses in polymeric hollow fiber membrane preparation, characterization and applicationsFeng, C. Y.; Khulbe, K. C.; Matsuura, T.; Ismail, A. F.Separation and Purification Technology (2013), 111 (), 43-71CODEN: SPUTFP; ISSN:1383-5866. (Elsevier B.V.)A review. Membrane sepn. using hollow fibers has become one of the emerging technologies which underwent a rapid growth during the past few decades. In this article, recent progresses (last 12 years) on polymeric hollow fiber membranes have been discussed. In particular, the following topics were identified as the recent trends in the hollow fiber research. Characterizations of membrane esp. by at. force microscopy (AFM) have been reported. New hollow fiber membranes for gas-sepn. have been developed. New polymers and techniques have been introduced in making high performance hollow fibers. Many PVDF based membranes have been developed. Orientation of polymer mol. during spinning was also investigated. However the mechanism of orientation is not fully investigated.
- 8Johnson, D. J.; Hilal, N. Nanocomposite Nanofiltration Membranes: State of Play and Recent Advances. Desalination 2022, 524, 115480 DOI: 10.1016/J.DESAL.2021.115480Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXis1GjtLfO&md5=4eec0df4c50d27ff6fab4400d87a5791Nanocomposite nanofiltration membranes: State of play and recent advancesJohnson, Daniel James; Hilal, NidalDesalination (2022), 524 (), 115480CODEN: DSLNAH; ISSN:0011-9164. (Elsevier B.V.)A review. Much research has been carried out in recent years to investigate the use of nanomaterials as fillers in polymeric nanofiltration membranes, to improve water transport and fouling resistance while preserving, where possible, selectivity. This review paper considers the background to this research, including membrane fabrication and incorporation of various nanomaterials and the addnl. functionalities achieved by nanomaterial incorporation, followed by a crit. review of the recent literature in this area. The research efforts which have accumulated in recent years shows great promise for improving the transport and fouling properties of NF membranes for a variety of applications, but this field is still immature and shows much room for further research. Despite this, caution must be made to ensure that research is focussed on practical solns., capable of being scaled up within com. acceptable constraints.
- 9Yang, Z.; Sun, P.-F.; Li, X.; Gan, B.; Wang, L.; Song, X.; Park, H.-D.; Tang, C. Y. A Critical Review on Thin-Film Nanocomposite Membranes with Interlayered Structure: Mechanisms, Recent Developments, and Environmental Applications. Environ. Sci. Technol. 2020, 54, 15563– 15583, DOI: 10.1021/ACS.EST.0C05377Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXitlOntr3K&md5=cbb3d18a7c73091e353be08e0d58edf2A Critical Review on Thin-Film Nanocomposite Membranes with Interlayered Structure: Mechanisms, Recent Developments, and Environmental ApplicationsYang, Zhe; Sun, Peng-Fei; Li, Xianhui; Gan, Bowen; Wang, Li; Song, Xiaoxiao; Park, Hee-Deung; Tang, Chuyang Y.Environmental Science & Technology (2020), 54 (24), 15563-15583CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)A review. The sepn. properties of polyamide reverse osmosis and nanofiltration membranes, widely applied for desalination and water reuse, are constrained by the permeability-selectivity upper bound. Although thin-film nanocomposite (TFN) membranes incorporating nanomaterials exhibit enhanced water permeance, their rejection is only moderately improved or even impaired due to agglomeration of nanomaterials and formation of defects. A novel type of TFN membranes featuring an interlayer of nanomaterials (TFNi) has emerged in recent years. These novel TFNi membranes show extraordinary improvement in water flux (e.g., up to an order of magnitude enhancement) along with better selectivity. Such enhancements can be achieved by a wide selection of nanomaterials, ranging from nanoparticles, one-/two-dimensional materials, to interfacial coatings. The use of nanostructured interlayers not only improves the formation of polyamide rejection layers but also provides an optimized water transport path, which enables TFNi membranes to potentially overcome the longstanding trade-off between membrane permeability and selectivity. Furthermore, TFNi membranes can potentially enhance the removal of heavy metals and micropollutants, which is crit. for many environmental applications. This review critically examines the recent developments of TFNi membranes and discusses the underlying mechanisms and design criteria. Their potential environmental applications are also highlighted.
- 10Zodrow, K.; Brunet, L.; Mahendra, S.; Li, D.; Zhang, A.; Li, Q.; Alvarez, P. J. J. Polysulfone Ultrafiltration Membranes Impregnated with Silver Nanoparticles Show Improved Biofouling Resistance and Virus Removal. Water Res. 2009, 43, 715– 723, DOI: 10.1016/J.WATRES.2008.11.014Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFelsb8%253D&md5=ec610b7c06515992084af9ada3d0259dPolysulfone ultrafiltration membranes impregnated with silver nanoparticles show improved biofouling resistance and virus removalZodrow, Katherine; Brunet, Lena; Mahendra, Shaily; Li, Dong; Zhang, Anna; Li, Qilin; Alvarez, Pedro J. J.Water Research (2009), 43 (3), 715-723CODEN: WATRAG; ISSN:0043-1354. (Elsevier Ltd.)Biofouling and virus penetration are two significant obstacles in water treatment membrane filtration. Biofouling reduces membrane permeability, increases energy costs, and decreases the lifetime of membranes. In order to effectively remove viruses, nanofiltration or reverse osmosis (both high energy filtration schemes) must be used. Thus, there is an urgent demand for low pressure membranes with anti-biofouling and antiviral properties. The antibacterial properties of silver are well known, and silver nanoparticles (nAg) are now incorporated into a wide variety of consumer products for microbial control. In this study, nAg incorporated into polysulfone ultrafiltration membranes (nAg-PSf) exhibited antimicrobial properties towards a variety of bacteria, including Escherichia coli K12 and Pseudomonas mendocina KR1, and the MS2 bacteriophage. Nanosilver incorporation also increased membrane hydrophilicity, reducing the potential for other types of membrane fouling. XPS anal. indicated a significant loss of silver from the membrane surface after a relatively short filtration period (0.4 L/cm2) even though ICP anal. of digested membrane material showed that 90% of the added silver remained in the membrane. This silver loss resulted in a significant loss of antibacterial and antiviral activity. Thus, successful fabrication of nAg-impregnated membranes needs to allow for the release of sufficient silver ions for microbial control while preventing a rapid depletion of silver.
- 11Ben-Sasson, M.; Zodrow, K. R.; Genggeng, Q.; Kang, Y.; Giannelis, E. P.; Elimelech, M. Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface Properties. Environ. Sci. Technol. 2014, 48, 384– 393, DOI: 10.1021/ES404232SGoogle Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvV2mt7nI&md5=b613e4793a3364a0a1c22707a9c1f3d6Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface PropertiesBen-Sasson, Moshe; Zodrow, Katherine R.; Genggeng, Qi; Kang, Yan; Giannelis, Emmanuel P.; Elimelech, MenachemEnvironmental Science & Technology (2014), 48 (1), 384-393CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)Biofouling is a major operational challenge in reverse osmosis (RO) desalination, motivating a search for improved biofouling control strategies. Copper, long known for its antibacterial activity and relatively low cost, is an attractive potential biocidal agent. The authors present a method for loading copper nanoparticles (Cu-NPs) on the surface of a thin-film composite (TFC) polyamide RO membrane. Cu-NPs were synthesized using polyethyleneimine (PEI) as a capping agent, resulting in particles with an av. radius of 34 nm and a copper content between 39 and 49%. The pos. charge of the Cu-NPs imparted by the PEI allowed a simple electrostatic functionalization of the neg. charged RO membrane. The authors confirmed functionalization and irreversible binding of the Cu-NPs to the membrane surface with SEM and XPS after exposing the membrane to bath sonication. Also Cu-NP functionalization can be repeated after the Cu-NPs dissolve from the membrane surface. The Cu-NP functionalization had minimal impact on the intrinsic membrane transport parameters. Surface hydrophilicity and surface roughness were also maintained, and the membrane surface charge became pos. after functionalization. The functionalized membrane exhibited significant antibacterial activity, leading to an 80-95% redn. in the no. of attached live bacteria for three different model bacterial strains. Challenges assocd. with this functionalization method and its implementation in RO desalination are discussed.
- 12Alhoshan, M.; Alam, J.; Dass, L. A.; Al-Homaidi, N. Fabrication of Polysulfone/ZnO Membrane: Influence of ZnO Nanoparticles on Membrane Characteristics. Adv. Polym. Technol. 2013, 32, 21369 DOI: 10.1002/ADV.21369Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1Shs7bM&md5=52410d2ffc0d1d6c2b2d1d4999dc7f00Fabrication of Polysulfone/ZnO Membrane: Influence of ZnO Nanoparticles on Membrane CharacteristicsAlhoshan, Mansour; Alam, Javed; Dass, Lawrence Arockiasamy; Al-Homaidi, NasserAdvances in Polymer Technology (2013), 32 (4), 21369/1-21369/7CODEN: APTYD5; ISSN:0730-6679. (John Wiley & Sons, Inc.)A mixed matrix membrane consisting of a polysulfone and nano-ZnO particles has been fabricated by a combination of soln. dispersion blending and phase-inversion method. The study is focused on the influence of ZnO on membrane morphol., surface roughness, and hydrophilicity, which were investigated through the methods of SEM, at. force microscopy, and contact angle meter, resp. In addn., the changes in membrane characteristics with the addn. nano-ZnO particles were examd. by pure water flux, water content and porosity, and salts rejection including NaCl and MgSO4. From the results, it was revealed that nano-ZnO particles constructed a membrane having more hydrophilic, smooth, and tightly packed surface, which offered a high flux and an effective permeability barrier. Moreover, it was obsd. that nano-ZnO particles produced spongy a membrane with uniform and well-interconnecting pores. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21369; View this article online at wileyonlinelibrary. com. DOI 10.1002/adv.21369.
- 13Escobar-Ferrand, L.; Li, D.; Lee, D.; Durning, C. J. All-Nanoparticle Layer-by-Layer Surface Modification of Micro- and Ultrafiltration Membranes. Langmuir 2014, 30, 5545– 5556, DOI: 10.1021/LA5002489Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtV2rtrc%253D&md5=84ca0afad4f5f2381e445b1068a10377All-Nanoparticle Layer-by-Layer Surface Modification of Micro- and Ultrafiltration MembranesEscobar-Ferrand, Luis; Li, Diya; Lee, Daeyeon; Durning, Christopher J.Langmuir (2014), 30 (19), 5545-5556CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Layer-by-layer (LbL) deposition using primarily inorg. silica nanoparticles is employed for surface modification of polymeric micro- and ultrafiltration (MF/UF) membranes to produce novel thin film composite (TFC) membranes intended for nanofiltration (NF) and reverse osmosis (RO) applications. A wide variety of porous substrate membranes with different surface characteristics are successfully employed. This report gives detailed results for polycarbonate track etched (PCTE), polyethersulfone (PES), and sulfonated PES (SPEES) MF/UF substrates. Both spherical (cationic/anionic) and eccentric elongated (anionic) silica nanoparticles are deposited using conditions similar to those in prior works for solid substrates (e.g., Lee et al.). Appropriate selection of the pH for anionic and cationic particle deposition enables construction of nanoparticle-only layers 100-1200 nm in thickness atop the original porous membrane substrates. The surface layer thickness appears to vary linearly with the no. of bilayers deposited, i.e., with the no. of anionic/cationic deposition cycles. The deposition process is optimized to eliminate drying-induced cracking and improve mech. durability via thickness control and postdeposition hydrothermal treatment. Dead-end permeation tests using dextran stds. reveal the hydraulic characteristics and sepns. capability for the PCTE-based TFC membranes. Nanoparticle-based LbL surface modification of MF and UF rated media can produce TFC membranes with NF capabilities.
- 14Soroko, I.; Livingston, A. Impact of TiO2 Nanoparticles on Morphology and Performance of Crosslinked Polyimide Organic Solvent Nanofiltration (OSN) Membranes. J. Membr. Sci. 2009, 343, 189– 198, DOI: 10.1016/J.MEMSCI.2009.07.026Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVOis7zF&md5=d824fcf2de2d42dcbe7920abeff035a6Impact of TiO2 nanoparticles on morphology and performance of crosslinked polyimide organic solvent nanofiltration (OSN) membranesSoroko, Iwona; Livingston, AndrewJournal of Membrane Science (2009), 343 (1-2), 189-198CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Chem. crosslinked polyimide org.-inorg. composite nanofiltration membranes suitable for application in harsh org. solvents were successfully prepd. by phase inversion of dope solns. TiO2 nanoparticles were dispersed in these dope solns., comprising polyimide (PI) in N,N-dimethylformamide/1,4-dioxane. The impact of TiO2 on the resulting PI membranes was studied using SEM, TGA, water contact angle, dope viscosity measurements and mech. strength. The presence of TiO2 nanoparticles within the membrane matrix was proved by the detection of a peak characteristic of TiO2 in the WAXS pattern. SEM pictures of the cross-section of the PI/TiO2 membranes showed dramatically changed morphol. compared to ref. membranes with no TiO2 addn. Macrovoids present in ref. membranes were suppressed by increasing loading of TiO2 nanoparticles, and eventually disappeared completely at a TiO2 loading above 3 wt.%. Decreasing water contact angle and an increase in ethanol flux indicated that hydrophilicity increased as nanoparticle loading increased. The effect of TiO2 on the functional performance of the membranes was evaluated by measuring flux and rejection using cross-flow filtration. Perhaps surprisingly, the presence of TiO2 improved the compaction resistance of the membranes, whereas rejection and steady flux were almost unaltered.
- 15Sun, M.; Su, Y.; Mu, C.; Jiang, Z. Improved Antifouling Property of PES Ultrafiltration Membranes Using Additive of Silica-PVP Nanocomposite. Ind. Eng. Chem. Res. 2010, 49, 790– 796, DOI: 10.1021/IE900560EGoogle Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsV2nur3M&md5=f6475ea6238374c4c9d7367a5e97660fImproved Antifouling Property of PES Ultrafiltration Membranes using Additive of Silica-PVP NanocompositeSun, Meng-Ping; Su, Yan-Lei; Mu, Chun-Xia; Jiang, Zhong-YiIndustrial & Engineering Chemistry Research (2010), 49 (2), 790-796CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)To improve the surface coverage of polyvinylpyrrolidone (PVP) on membrane surfaces and further enhance the antifouling property, a silica-PVP nanocomposite was synthesized and used as a novel hydrophilic additive to modify polyethersulfone (PES) membranes. Transmission electron microscopy (TEM) observation showed that PES membranes, using additives of PVP and silica-PVP nanocomposites, have similar asym. structures. XPS measurement indicated that the near-surface coverage of PVP for PES membrane with a silica-PVP nanocomposite additive is greater than that with a PVP additive. Protein ultrafiltration expt. also showed that the antifouling ability of PES membrane with a silica-PVP nanocomposite additive is stronger than that with a PVP additive. The hydrophilic modification with a silica-PVP nanocomposite is an appropriate method for improved antifouling property of PES ultrafiltration membranes.
- 16Haase, M. F.; Jeon, H.; Hough, N.; Kim, J. H.; Stebe, K. J.; Lee, D. Multifunctional Nanocomposite Hollow Fiber Membranes by Solvent Transfer Induced Phase Separation. Nat. Commun. 2017, 8, 1234 DOI: 10.1038/s41467-017-01409-3Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M7msVSisQ%253D%253D&md5=e6ab18c5803bd8cb0852a426240e10a7Multifunctional nanocomposite hollow fiber membranes by solvent transfer induced phase separationHaase Martin F; Hough Noah; Jeon Harim; Stebe Kathleen J; Lee Daeyeon; Jeon Harim; Kim Jong HakNature communications (2017), 8 (1), 1234 ISSN:.The decoration of porous membranes with a dense layer of nanoparticles imparts useful functionality and can enhance membrane separation and anti-fouling properties. However, manufacturing of nanoparticle-coated membranes requires multiple steps and tedious processing. Here, we introduce a facile single-step method in which bicontinuous interfacially jammed emulsions are used to form nanoparticle-functionalized hollow fiber membranes. The resulting nanocomposite membranes prepared via solvent transfer-induced phase separation and photopolymerization have exceptionally high nanoparticle loadings (up to 50 wt% silica nanoparticles) and feature densely packed nanoparticles uniformly distributed over the entire membrane surfaces. These structurally well-defined, asymmetric membranes facilitate control over membrane flux and selectivity, enable the formation of stimuli responsive hydrogel nanocomposite membranes, and can be easily modified to introduce antifouling features. This approach forms a foundation for the formation of advanced nanocomposite membranes comprising diverse building blocks with potential applications in water treatment, industrial separations and as catalytic membrane reactors.
- 17Haase, M. F.; Stebe, K. J.; Lee, D. Continuous Fabrication of Hierarchical and Asymmetric Bijel Microparticles, Fibers, and Membranes by Solvent Transfer-Induced Phase Separation (STRIPS). Adv. Mater. 2015, 27, 7065– 7071, DOI: 10.1002/ADMA.201503509Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1Slu77I&md5=e4f4ae7858d773078101d6c7dbf657a2Continuous Fabrication of Hierarchical and Asymmetric Bijel Microparticles, Fibers, and Membranes by Solvent Transfer-Induced Phase Separation (STRIPS)Haase, Martin F.; Stebe, Kathleen J.; Lee, DaeyeonAdvanced Materials (Weinheim, Germany) (2015), 27 (44), 7065-7071CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A scalable method for continuous fabrication of hierarchically and asym. structured bijel microparticles, fibers, and membranes via STRIPS using ternary liq. mixts. is presented. The resulting fibers are indeed bicontinuous as demonstrated by the transport of mols. of differing polarity within the structure. STRIPS provides several advantages that make it a highly translatable technique for bijel formation. Compared to the conventional method that uses binary liq. mixts., wide varieties of immiscible liq. combinations can be used for bijel prepn. The fast quenching of the ternary mixt. by STRIPS allows for the formation of hierarchical and asym. microstructures with submicron features, which expands the potential of bijels in various applications.
- 18Park, T.; Choi, G. H.; Lee, D.; Yoo, P. Y. Metal-Phenolic Network-Coated Hollow Fiber Catalytic Membranes via Solvent Transfer Induced Phase Separation (STRIPS) for Suzuki Coupling Reaction. J. Membr. Sci. 2021, 634, 119386 DOI: 10.1016/J.MEMSCI.2021.119386Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtFSgs7%252FO&md5=2688d0776b63a4dd30f9ca3828d1f0c2Metal-phenolic network-coated hollow fiber catalytic membranes via solvent transfer induced phase separation (STRIPS) for Suzuki coupling reactionPark, Taejung; Choi, Gwan H.; Lee, Daeyeon; Yoo, Pil J.Journal of Membrane Science (2021), 634 (), 119386CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Catalytically reactive membranes enable continuous and high yield chem. reactions while obviating the need for catalyst sepn. from the product stream. Despite recent advances, there still exists considerable challenges in developing high performance catalytic membranes. Most works to date have used planar membranes made of chem. inert materials, limiting conversion efficiency due to their low sp. surface area and difficulty assocd. with incorporating a high d. of catalytic nanoparticles on their surface. To overcome these limitations, we employ a single-step solvent transfer-induced phase sepn. (STRIPS) method to prep. nanocomposite hollow fiber membranes. Taking advantage of a dense layer of silica nanoparticles (NPs) on the surface of the STRIPS membrane, catalytic activity is imbued by coating the membrane surface with palladium (Pd)-supported metal-phenolic network (MPN). These catalytic hollow fiber membranes are used to perform Suzuki-Miyaura cross-coupling reactions, enabling continuous prodn. of biaryl compds. with a high conversion efficiency (>90%) while retaining high permeability (>60 L/m2·h (LMH) at 1 bar-pressurized condition). The approach presented in this work synergistically combines hollow fiber nanocomposite structures and MPN coating to offer a versatile platform for developing the next generation reactive membranes for synthesizing valuable chems.
- 19Tran, L.; Haase, M. F. Templating Interfacial Nanoparticle Assemblies via in Situ Techniques. Langmuir 2019, 35, 8584– 8602, DOI: 10.1021/ACS.LANGMUIR.9B00130Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXjvVyks78%253D&md5=ba94c2cf4698c0a2c5ae6631733ebe95Templating Interfacial Nanoparticle Assemblies via in Situ TechniquesTran, Lisa; Haase, Martin F.Langmuir (2019), 35 (26), 8584-8602CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)A review. In situ surface modification of nanoparticles has a rich industrial history, but in recent years, it has also received increased attention in the field of directed self-assembly. In situ techniques rely on components within a Pickering emulsion system, such as amphiphiles that act as hydrophobizers or ionic species that screen charges, to drive the interfacial assembly of particles. Instead of stepwise procedures to chem. tune the particle wettability, in situ methods use elements already present within the system to alter the nanoparticle interfacial behavior, often depending on Coulombic interactions to simplify operations. The surface modifications are not contingent on specific chem. reactions, which further enables a multitude of possible nanoparticles to be used within a given system. In recent studies, in situ methods have been combined with external means of shaping the interface to produce materials with high interfacial areas and complex geometries. These systems have facilely tunable properties, enabling their use in an extensive array of applications. In this feature article, in honor of the late Prof. Helmuth M.ovrddot.ohwald, we review how in situ techniques have influenced the development of soft, advanced materials, covering the fundamental interfacial phenomena with an outlook on materials science.
- 20Boakye-Ansah, S.; Schwenger, M. S.; Haase, M. F. Designing Bijels Formed by Solvent Transfer Induced Phase Separation with Functional Nanoparticles. Soft Matter 2019, 15, 3379– 3388, DOI: 10.1039/C9SM00289HGoogle Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlvVWrs78%253D&md5=628c88c62d2902c72addcc35b9d5dd25Designing bijels formed by solvent transfer induced phase separation with functional nanoparticlesBoakye-Ansah, Stephen; Schwenger, Matthew S.; Haase, Martin F.Soft Matter (2019), 15 (16), 3379-3388CODEN: SMOABF; ISSN:1744-6848. (Royal Society of Chemistry)Bicontinuous interfacially jammed emulsion gels (bijels) formed via solvent transfer induced phase sepn. (STrIPS) are new soft materials with potential applications in sepns., healthcare, or catalysis. To facilitate their applications, means to fabricate STrIPS bijels with nanoparticles of various surface chemistries are needed. Here, we investigate the formation of STrIPS bijels with nanoparticles of different wettabilities, ranging from partially hydrophobic to extremely hydrophilic. To this end, the surface wettability of silica nanoparticles is tailored by functionalization with ligands bearing either hydrophobic or hydrophilic terminal groups. We show that partially hydrophobic particles with acrylate groups can impart short-term stability to STrIPS bijels on their own. However, to enable long-term stability, the use of cationic surfactants is needed. Partially hydrophobic particles require short chain surfactants for morphol. stability while glycerol-functionalized hydrophilic particles require double chain cationic surfactants. Variation of the surfactant concn. results in various STrIPS bijel morphologies with controllable domain sizes. Last, we show that functional groups on the nanoparticles facilitate interfacial crosslinking for the purposes of reinforcing STrIPS bijels. Our research lays the foundation for the use of a wide variety of solid particles, irresp. of their surface wettabilities, to fabricate bijels with potential applications in Pickering interfacial catalysis and as cross-flow microreactors.
- 21Boakye-Ansah, S.; Khan, M. A.; Haase, M. F. Controlling Surfactant Adsorption on Highly Charged Nanoparticles to Stabilize Bijels. J. Phys. Chem. C 2020, 124, 12417– 12423, DOI: 10.1021/ACS.JPCC.0C01440Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXpt1Olt7w%253D&md5=15ad6c3c07a7e4d1cff8de7a8c830d6cControlling Surfactant Adsorption on Highly Charged Nanoparticles to Stabilize BijelsBoakye-Ansah, Stephen; Khan, Mohd Azeem; Haase, Martin F.Journal of Physical Chemistry C (2020), 124 (23), 12417-12423CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Bicontinuous particle-stabilized emulsions (bijels) are networks of interpenetrating oil/water channels with applications in catalysis, tissue engineering, and energy storage. Bijels can be generated by arresting solvent transfer induced phase sepn. (STrIPS) via interfacial jamming of nanoparticles. However, until now, STrIPS bijels have only been formed with silica nanoparticles of low surface charge densities, limiting their potential applications in catalysis and fluid transport. Here, we show how strongly charged silica nanoparticles can stabilize bijels. To this end, we carry out a systematic study employing dynamic light scattering, zeta potential, acid/base titrns., turbidimetry, surface tension, and confocal microscopy. We find that moderating the adsorption of oppositely charged surfactants on the particles is crucial to facilitate particle dispersibility in the bijel casting mixt. and bijel stabilization. Our results potentially introduce a general understanding for bijel fabrication with different inorg. nanoparticle materials of variable charge d.
- 22Khan, M. A.; Sprockel, A. J.; Macmillan, K. A.; Alting, M. T.; Kharal, S. P.; Boakye-Ansah, S.; Haase, M. F. Nanostructured, Fluid-Bicontinuous Gels for Continuous-Flow Liquid-Liquid Extraction. Adv. Mater. 2022, 34, 2109547 DOI: 10.1002/ADMA.202109547Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XovVyqurY%253D&md5=4f69a400e6aab88bcb4f615555d98ff9Nanostructured, Fluid-Bicontinuous Gels for Continuous-Flow Liquid-Liquid ExtractionKhan, Mohd A.; Sprockel, Alessio J.; Macmillan, Katherine A.; Alting, Meyer T.; Kharal, Shankar P.; Boakye-Ansah, Stephen; Haase, Martin F.Advanced Materials (Weinheim, Germany) (2022), 34 (18), 2109547CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)Fluid-bicontinuous gels are unique materials that allow two distinct fluids to interact through a percolating, rigid scaffold. Current restrictions for their use are the large fluid-channel sizes (>5 μm), limiting the fluid-fluid interaction surface-area, and the inability to flow liqs. through the channels. In this work a scalable synthesis route of nanoparticle stabilized fluid-bicontinuous gels with channels sizes below 500 nm and sp. surface areas of 2 m2 cm-3 is introduced. Moreover, it is demonstrated that liqs. can be pumped through the fluid-bicontinuous gels via electroosmosis. The fast liq. flow in the fluid-bicontinuous gel facilitates their use for mol. sepns. in continuous-flow liq.-liq. extn. Together with the high surface areas, liq. flow through fluid-bicontinuous gels enhances their potential as highly permeable porous materials with possible uses as microreaction media, fuel-cell components, and sepn. membranes.
- 23Kharal, S. P.; Haase, M. F. Centrifugal Assembly of Helical Bijel Fibers for pH Responsive Composite Hydrogels. Small 2022, 18, 2106826 DOI: 10.1002/SMLL.202106826Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhslCgsrY%253D&md5=7b8db2761549fff0d8c4f9b1c5861aa0Centrifugal Assembly of Helical Bijel Fibers for pH Responsive Composite HydrogelsKharal, Shankar P.; Haase, Martin F.Small (2022), 18 (11), 2106826CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)In microfluidics, centrifugal forces are important for centrifugal microfluidic chips and curved microchannels. Here, an unrecognized use of the centrifugal effect in microfluidics is introduced. The assembly of helical soft matter fibers in a rotating microcapillary is investigated. During assembly, the fibers undergo phase sepn., generating particle stabilized bicontinuous interfacially jammed emulsions gels. This process is accompanied by a transition of the fiber d. over time. As a result, the direction of the centrifugal force in the rotating microcapillary changes. The authors analyze this effect systematically with high-speed video microscopy and complementary computer simulations. The resulting understanding enables the control of the helical fiber assembly into microropes. These microropes can be converted into pH responsive hydrogels that swell and shrink with potential applications in tissue engineering, soft robotics, controlled release, and sensing. More generally, the knowledge gained from this work shows that centrifugal forces potentially enable directed self-assembly or sepn. of colloids, biol. cells, and emulsions in microfluidics.
- 24Kharal, S. P.; Hesketh, R. P.; Haase, M. F. High-Tensile Strength, Composite Bijels through Microfluidic Twisting. Adv. Funct. Mater. 2020, 30, 2003555 DOI: 10.1002/ADFM.202003555Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlegtbrP&md5=e718279cc3859cf90fbd145e89a3d2afHigh-Tensile Strength, Composite Bijels through Microfluidic TwistingKharal, Shankar P.; Hesketh, Robert P.; Haase, Martin F.Advanced Functional Materials (2020), 30 (35), 2003555CODEN: AFMDC6; ISSN:1616-301X. (Wiley-VCH Verlag GmbH & Co. KGaA)Rope making is a millennia old technique to collectively assemble numerous weak filaments into flexible and high tensile strength bundles. However, delicate soft matter fibers lack the robustness to be twisted into bundles by means of mech. rope making tools. Here, weak microfibers with tensile strengths of a few kilopascals are combined into ropes via microfluidic twisting. This is demonstrated for recently introduced fibers made of bicontinuous interfacially jammed emulsion gels (bijels). Bijels show promising applications in use as membranes, microreactors, energy and healthcare materials, but their low tensile strength make reinforcement strategies imperative. Hydrodynamic twisting allows to produce continuous bijel fiber bundles of controllable architecture. Modeling the fluid flow field reveals the bundle geometry dependence on a subtle force balance composed of rotational and translational shear stresses. Moreover, combining multiple bijel fibers of different compns. enables the introduction of polymeric support fibers to raise the tensile strength to tens of megapascals, while simultaneously preserving the liq. like properties of the bijel fibers for transport applications. Hydrodynamic twisting shows potentials to enable the combination of a wide range of materials resulting in composites with features greater than the sum of their parts.
- 25Joseph, N.; Ahmadiannamini, P.; Hoogenboom, R.; Vankelecom, I. F. J. Layer-by-Layer Preparation of Polyelectrolyte Multilayer Membranes for Separation. Polym. Chem. 2014, 5, 1817– 1831, DOI: 10.1039/C3PY01262JGoogle Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXivFWqsb4%253D&md5=0972319234c36e7e354f7eea766b8a6eLayer-by-layer preparation of polyelectrolyte multilayer membranes for separationJoseph, Nithya; Ahmadiannamini, Pejman; Hoogenboom, Richard; Vankelecom, Ivo. F. J.Polymer Chemistry (2014), 5 (6), 1817-1831CODEN: PCOHC2; ISSN:1759-9962. (Royal Society of Chemistry)A review. Polymer membranes provide a highly promising platform for the development of an efficient and sustainable technique for sepn. Ideally such membranes combine a high flux with a high selectivity requiring thin defect-free membranes. The layer by layer (LBL) assembly technique has proven to be a versatile and simple method for the fabrication of very thin polyelectrolyte multilayers making it highly suitable for the prepn. of sepn. membranes. Recent developments in this field related to membrane prepn. and their applications in sepn. processes are presented and discussed in this review. An overview of the different fabrication techniques of such membranes will be first provided. In addn., the formation mechanism and the parameters that can be varied to tune the properties of the membranes will be discussed. Finally, the potential applications of these membranes in different sepn. areas such as pervaporation, nanofiltration, solvent resistant nanofiltration, reverse osmosis, gas sepn. and forward osmosis will be addressed.
- 26Reurink, D. M.; Willott, J. D.; Roesink, H. D. W.; de Vos, W. M. Role of Polycation and Cross-Linking in Polyelectrolyte Multilayer Membranes. ACS Appl. Polym. Mater. 2020, 2, 5278– 5289, DOI: 10.1021/ACSAPM.0C00992Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXit1arsb3M&md5=aed37b3ce6129721152a2b61eb9d5fecRole of Polycation and Cross-Linking in Polyelectrolyte Multilayer MembranesReurink, D. M.; Willott, J. D.; Roesink, H. D. W.; de Vos, W. M.ACS Applied Polymer Materials (2020), 2 (11), 5278-5289CODEN: AAPMCD; ISSN:2637-6105. (American Chemical Society)Alternate deposition of oppositely charged polyelectrolytes is an excellent approach to control the chem. of interfaces. Membrane technol. is one field that benefits from the simplicity and tunability of polyelectrolyte multilayers (PEMs). Herein, ultrafiltration support membranes are coated with PEMs to fabricate nanofiltration membranes. Three PEMs, of different polymeric structures, namely, those of poly(4-styrene sulfonate) (PSS)/poly(allylamine hydrochloric acid) (PAH), PSS/poly(ethyleneimine) (PEI, branched), and PSS/poly(4-aminostyrene) (PAS), are prepd. and studied from a fundamental perspective in terms of multilayer compn. and crosslinking and also from an applied perspective through PEM membrane performance. The low mol. wt. cutoff (MWCO) of the PSS/PAH membranes signifies their dense structure (small mesh size), while ion retentions indicate that the dielec. exclusion mechanism is dominant. The PSS/PEI membranes are even denser and have higher selectivities. In contrast, the PSS/PAS membranes are more open, which is likely due to the lower charge d. of PAS compared to PEI and PAH. After chem. crosslinking, all of the PEM membranes are denser and therefore more selective and less permeable to water. Micropollutant retention increases for crosslinked PSS/PAH membranes, whereas little to no improvement is seen for crosslinked PSS/PAS and PSS/PEI membranes. Overall, this study shows that completely different membrane properties can be obtained by changing the type of polycation, thus demonstrating the high versatility of PEM-based membranes. In addn., for all PEM membranes, crosslinking acts as an addnl. tuning parameter that leads to denser and typically more selective layers.
- 27Kamp, J.; Emonds, S.; Wessling, M. Designing Tubular Composite Membranes of Polyelectrolyte Multilayer on Ceramic Supports with Nanofiltration and Reverse Osmosis Transport Properties. J. Membr. Sci. 2021, 620, 118851 DOI: 10.1016/J.MEMSCI.2020.118851Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXisVGlurnM&md5=02c63843c046e2cef04903504aa5d3d6Designing tubular composite membranes of polyelectrolyte multilayer on ceramic supports with nanofiltration and reverse osmosis transport propertiesKamp, Johannes; Emonds, Stephan; Wessling, MatthiasJournal of Membrane Science (2021), 620 (), 118851CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Ceramic membranes are relevant for applications, which require mech. robustness and chem. stability. The prepn. of purely ceramic membranes for nanofiltration (NF) and reverse osmosis (RO) is a demanding process. Composite membranes comprise a mech. stable ceramic support and a functional polymeric sepn. layer, combining the advantages of both worlds. In this work, we present a mol. strategy to fabricate polyelectrolyte multi-layer membranes (PEMM) ranging from dense nanofiltration into the region of reverse osmosis deposited on tubular ceramic supports. A dynamic coating of PAH/PSS on a α-Al2O3 support membrane with pore sizes of 150 nm (MF) and 50 nm (UF) leads to a dense sepn. layer on the lumen side, with NaCl rejections above 90%. Coating solns. with increased ionic strength, as well as a subsequent covalent crosslinking of the amine groups of the PAH improve long term stability. The substitution of the polyanion PSS by PVSA, having a higher charge d., results in a remarkably low MWCO of 115 Da. This work indicates that balancing the charge d. of polymers with the ionic matrix can result in reverse osmosis type selective layers on ceramic support with pore size even as large as 150 nm.
- 28Stanton, B. W.; Harris, J. J.; Miller, M. D.; Bruening, M. L. Ultrathin, Multilayered Polyelectrolyte Films as Nanofiltration Membranes. Langmuir 2003, 19, 7038– 7042, DOI: 10.1021/LA034603AGoogle Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXltFKqur8%253D&md5=d257495bb65333a112677ec90bed0ff7Ultrathin, multilayered polyelectrolyte films as nanofiltration membranesStanton, Brian W.; Harris, Jeremy J.; Miller, Matthew D.; Bruening, Merlin L.Langmuir (2003), 19 (17), 7038-7042CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)This study shows that alternating polyelectrolyte deposition on porous supports can yield nanofiltration membranes that allow high water flux along with selective ion transport. Membranes composed of 4.5-5 layer pairs of poly(styrene sulfonate)/poly(allylamine hydrochloride) (PSS/PAH) on porous alumina allow water fluxes of 1-2 m3 m-2 day-1 at 4.8 bar while exhibiting MgSO4 rejections of 96%. Rejections of CaCl2 and Na2SO4 depend on polyelectrolyte deposition conditions and the compn. of the outer layer of the membrane. In general, divalent-ion rejection increases when the charge of the outer layer of the membrane has the same sign as the divalent ion being rejected. Increasing the concn. of the supporting electrolyte present during deposition of the terminating PSS layer of PSS/PAH membranes results in a higher surface charge, and hence higher Na2SO4 rejections (up to 95%). Nanofiltration with mixed solns. of NaCl and Na2SO4 yields Cl-/SO42- selectivities of about 30 when the top layer of PSS/PAH membranes is deposited from a soln. of high ionic strength. Capping PSS/PAH films with a layer of PAA increases Cl-/SO42- selectivities to values as high as 80. Interestingly, Cl-/SO42- selectivities in mixed solns. are higher than those detd. from single-salt measurements, presumably because diffusion potentials are different in the two cases. The high selectivities, water fluxes, and ion rejections of PSS/PAH membranes make them potentially attractive for applications in water and salt purifn.
- 29Jin, W.; Toutianoush, A.; Tieke, B. Use of Polyelectrolyte Layer-by-Layer Assemblies as Nanofiltration and Reverse Osmosis Membranes. Langmuir 2003, 19, 2550– 2553, DOI: 10.1021/LA020926FGoogle Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhslCmurs%253D&md5=b42ac6b5090d0f4c3fa8417fcc358f4eUse of Polyelectrolyte Layer-by-Layer Assemblies as Nanofiltration and Reverse Osmosis MembranesJin, Wanqin; Toutianoush, Ali; Tieke, BerndLangmuir (2003), 19 (7), 2550-2553CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Measurements of ion transport and water flux across ultrathin multilayered membranes of polyelectrolytes were carried out under nanofiltration and reverse osmosis conditions. The polyelectrolyte membranes were prepd. upon alternating electrostatic layer-by-layer adsorption of poly(vinylamine) (PVA) and poly(vinyl sulfate) (PVS) on porous supports. The pressure-driven transport of aq. electrolyte solns. contg. NaCl, Na2SO4, MgCl2, and MgSO4 in 1 and 10 mM concn. was investigated. For MgCl2 and MgSO4, a complete rejection was obsd. independently from the concn. of the feed soln. and the pressure applied. For NaCl and Na2SO4, the rejections were 84 and 96% at 5 bar, and 93.5 and 98.5% at 40 bar, resp. The hydraulic permeability of the composite membrane was 113.7 mL/(m2 h bar). It was only little affected by the presence of salt. At low and moderate pressure the membranes are suitable for water softening applications, while at pressures of 40 bar or higher they can be used for water desalination. Effects of the stirring of the feed soln. on the membrane characteristics are also discussed.
- 30Virga, E.; de Grooth, J.; Žvab, K. J.; de Vos, W. M. Stable Polyelectrolyte Multilayer-Based Hollow Fiber Nanofiltration Membranes for Produced Water Treatment. ACS Appl. Polym. Mater. 2019, 1, 2230– 2239, DOI: 10.1021/ACSAPM.9B00503Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtlKlsbfO&md5=d55186abbe4c6790c2d03143ac0b99a4Stable Polyelectrolyte Multilayer-Based Hollow Fiber Nanofiltration Membranes for Produced Water TreatmentVirga, Ettore; de Grooth, Joris; Zvab, Klara; de Vos, Wiebe M.ACS Applied Polymer Materials (2019), 1 (8), 2230-2239CODEN: AAPMCD; ISSN:2637-6105. (American Chemical Society)Produced water (PW) constitutes a massive environmental issue due to its huge global prodn. as well as its complexity and toxicity. Membrane technol. could, however, convert this complex waste stream into an important source of water for reuse, but new and more efficient membranes are required. In particular, in the last few years, polyelectrolyte multilayers (PEMs) established themselves as a very powerful method to prep. hollow fiber-based nanofiltration (NF) membranes, and this membrane type and geometry would be ideal for PW treatment. Unfortunately, the presence of surfactants in PW can affect the stability of polyelectrolyte multilayers. In this work, we investigate the stability of polyelectrolyte multilayers toward different types of surfactant, initially on model surfaces. We find that chem. stable multilayers such as poly(diallyldimethylammonium chloride) (PDADMAC)/poly(sodium 4-styrenesulfonate) (PSS), based only on electrostatic interactions, are substantially desorbed by charged surfactants. For poly(allylamine hydrochloride) (PAH)/PSS multilayers, however, we demonstrate that chem. crosslinking by glutaraldehyde leads to surfactant stable layers. These stable PEM coatings can also be applied on hollow fiber support membranes to create hollow fiber NF membranes dedicated for PW treatment. Increased crosslinking time leads to more stable and more selective sepn. performance. These newly developed membranes were subsequently studied for the treatment of synthetic PW, consisting of freshly prepd. oil-in-water emulsions stabilized by hexade-cyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) in the presence of a mixt. of ions. For both types of produced water, the membranes show excellent oil removal (∼100%) and orgs. removal (TOC reduced up to ∼97%) as well as good divalent ion retentions (∼75% for Ca2+ and up to ∼80% for SO42-). Moreover, we observe a high flux recovery for both emulsions (100% for CTAB and 80% for SDS) and esp. for the CTAB emulsion a very low degree of fouling. These stable PEM-based hollow fiber membranes thus allow simultaneous deoiling and removal of small org. mols., particles, and divalent ions in a single step process while also demonstrating excellent membrane cleanability.
- 31Stratford, K.; Adhikari, R.; Pagonabarraga, I.; Desplat, J. C.; Cates, M. E. Colloidal Jamming at Interfaces: A Route to Fluid-Bicontinuous Gels. Science 2005, 309, 2198– 2201, DOI: 10.1126/SCIENCE.1116589Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVeksbnN&md5=bf8db2fa60b4c75759c761798e8600a1Colloidal Jamming at Interfaces: A Route to Fluid-Bicontinuous GelsStratford, K.; Adhikari, R.; Pagonabarraga, I.; Desplat, J.-C.; Cates, M. E.Science (Washington, DC, United States) (2005), 309 (5744), 2198-2201CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Colloidal particles or nanoparticles, with equal affinity for two fluids, are known to adsorb irreversibly to the fluid-fluid interface. We present large-scale computer simulations of the demixing of a binary solvent contg. such particles. The newly formed interface sequesters the colloidal particles; as the interface coarsens, the particles are forced into close contact by interfacial tension. Coarsening is markedly curtailed, and the jammed colloidal layer seemingly enters a glassy state, creating a multiply connected, solidlike film in three dimensions. The resulting gel contains percolating domains of both fluids, with possible uses as, for example, a microreaction medium.
- 32Herzig, E. M.; White, E. A.; Schofield, A. B.; Poon, W. C. K.; Clegg, P. S. Bicontinuous Emulsions Stabilized Solely by Colloidal Particles. Nat. Mater. 2007, 6, 966– 971, DOI: 10.1038/nmat2055Google Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlOmtL3L&md5=de2b813a1236db36597fc72f82873b55Bicontinuous emulsions stabilized solely by colloidal particlesHerzig, E. M.; White, K. A.; Schofield, A. B.; Poon, W. C. K.; Clegg, P. S.Nature Materials (2007), 6 (12), 966-971CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Recent large-scale computer simulations suggest that it may be possible to create a new class of soft solids, called bijels, by stabilizing and arresting the bicontinuous interface in a binary liq. demixing via spinodal decompn. using particles that are neutrally wetted by both liqs. The interfacial layer of particles is expected to be semi-permeable; hence, if realized, these new materials would have many potential applications, for example, as micro-reaction media. However, the creation of bijels in the lab. faces serious obstacles. In general, fast quench rates are necessary to bypass nucleation, so that only samples with limited thickness can be produced, which destroys the 3-dimensionality of the putative bicontinuous network. Also, even a small degree of unequal wettability of the particles by the 2 liqs. can lead to ill-characterized, lumpy interfacial layers and therefore irreproducible material properties. Here, the authors report a reproducible protocol for creating 3-dimensional samples of bijel in which the interfaces are stabilized by essentially a single layer of particles. To tune the mean interfacial sepn. in these bijels, and show that mech., they indeed behave as soft solids. These characteristics and their tunability will be of great value for microfluidic applications.
- 33Alvarez, N. J.; Walker, L. M.; Anna, S. L. A Non-Gradient Based Algorithm for the Determination of Surface Tension from a Pendant Drop: Application to Low Bond Number Drop Shapes. J. Colloid Interface Sci. 2009, 333, 557– 562, DOI: 10.1016/J.JCIS.2009.01.074Google Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXktVCmsr0%253D&md5=f1e27556288a907784b74d7a7f5d0856A non-gradient based algorithm for the determination of surface tension from a pendant drop: Application to low Bond number drop shapesAlvarez, Nicolas J.; Walker, Lynn M.; Anna, Shelley L.Journal of Colloid and Interface Science (2009), 333 (2), 557-562CODEN: JCISA5; ISSN:0021-9797. (Elsevier B.V.)The pendant drop method is one of the most widely used techniques to measure the surface tension between gas-liq. and liq.-liq. interfaces. The method consists of fitting the Young-Laplace equation to the digitized shape of a drop suspended from the end of a capillary tube. The 1st use of digital computers to solve this problem used nonlinear least squares fitting and since then numerous subroutines and algorithms were reported for improving efficiency and accuracy. However, current algorithms which rely on gradient based methods have difficulty converging for almost spherical drop shapes (i.e. low Bond nos.). The authors present a nongradient based algorithm based on the Nelder-Mead simplex method to solve the least squares problem. The main advantage of using a nongradient based fitting routine is that it is robust against poor initial guesses and works for almost spherical bubble shapes. The authors have tested the algorithm against theor. and exptl. drop shapes to demonstrate both the efficiency and the accuracy of the fitting routine for a wide range of Bond nos. This algorithm allows for surface tension measurements corresponding to Bond nos. previously shown to be ill suited for pendant drop measurements.
- 34Khan, M. A.; Haase, M. F. Stabilizing Liquid Drops in Nonequilibrium Shapes by the Interfacial Crosslinking of Nanoparticles. Soft Matter 2021, 17, 2034– 2041, DOI: 10.1039/D0SM02120BGoogle Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXmsVKqsg%253D%253D&md5=855163573afc2ea8545ac8d9f201e190Stabilizing liquid drops in nonequilibrium shapes by the interfacial crosslinking of nanoparticlesKhan, Mohd A.; Haase, Martin F.Soft Matter (2021), 17 (8), 2034-2041CODEN: SMOABF; ISSN:1744-6848. (Royal Society of Chemistry)Droplets are spherical due to the principle of interfacial energy minimization. Here, we show that nonequil. droplet shapes can be stabilized via the interfacial self-assembly and crosslinking of nanoparticles. This principle allows for the stability of practically infinitely long liq. tubules and monodisperse cylindrical droplets. Droplets of oil-in-water are elongated via gravitational or hydrodynamic forces at a reduced interfacial tension. Silica nanoparticles self-assemble and crosslink on the interface triggered by the synergistic surface modification with hexyltrimethylammonium- and trivalent lanthanum-cations. The droplet length dependence is described by a scaling relationship and the rate of nanoparticle deposition on the droplets is estd. Our approach potentially enables the 3D-printing of Newtonian Fluids, broadening the array of material options for additive manufg. techniques.
- 35Kang, Z.; Yeung, A.; Foght, J. M.; Gray, M. R. Mechanical Properties of Hexadecane–Water Interfaces with Adsorbed Hydrophobic Bacteria. Colloids Surf., B 2008, 62, 273– 279, DOI: 10.1016/J.COLSURFB.2007.10.021Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXisVWjt7o%253D&md5=e83af4b63db584ab259e50f90f6de77fMechanical properties of hexadecane-water interfaces with adsorbed hydrophobic bacteriaKang, Zhewen; Yeung, Anthony; Foght, Julia M.; Gray, Murray R.Colloids and Surfaces, B: Biointerfaces (2008), 62 (2), 273-279CODEN: CSBBEQ; ISSN:0927-7765. (Elsevier B.V.)This study focuses on how intact, hydrophobic bacteria in their stationary (i.e., non-dividing) phase could adsorb onto the hexadecane-water interface and alter its mech. properties. The two strains of bacteria used in forming the interfacial films were Acinetobacter venetianus RAG-1 and Rhodococcus erythropolis 20S-E1-c. Using the dynamic pendant drop technique, the film interfacial tension was monitored as the surface area was made to undergo transient changes. Under static conditions, both types of bacteria had no effect on the interfacial tension. When subjected to transient excitations, however, the two bacterial films exhibited clear and qual. similar rheol. properties: they responded as two-dimensional Maxwellian materials when the interfacial areas were dilated suddenly, but appeared to be purely elastic upon rapid area compression. Such rheol. behaviors are "non-linear" in that the responses of the tension to area dilation and contraction are not mirror images of one another. Despite their qual. similarities, the two types of film had very distinct film elasticities and relaxation times. The most striking difference between the two bacterial films was revealed under continuous redn. of area, when the A. venetianus RAG-1 system displayed a "paper-like" interface, whereas the interface of the R. erythropolis 20S-E1-c system was "soap film-like". These macroscopic observations could be explained by the surface ultrastructures of the two cell strains detd. using transmission electron microscopy.
- 36Binks, B. P.; Horozov, T. S. Colloidal Particles at Liquid Interfaces; Cambridge University Press, 2006; p 48.Google ScholarThere is no corresponding record for this reference.
- 37Stocco, A.; Nobili, M. A Comparison between Liquid Drops and Solid Particles in Partial Wetting. Adv. Colloid Interface Sci. 2017, 247, 223– 233, DOI: 10.1016/J.CIS.2017.06.014Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFyhs7fM&md5=8dd63784fdde2455724abd92195df48cA comparison between liquid drops and solid particles in partial wettingStocco, Antonio; Nobili, MaurizioAdvances in Colloid and Interface Science (2017), 247 (), 223-233CODEN: ACISB9; ISSN:0001-8686. (Elsevier B.V.)A review. In this crit. review we compare two geometries in partial wetting: a liq. drop on a planar substrate and a spherical particle at a planar liq. interface. We show that this comparison is far from being trivial even if the same phys. interactions are at play in both geometries. Similarities and differences in terms of free energies and frictions will be discussed. Contact angle hysteresis, the impact of surface roughness and line pinning on wetting will be described and compared to selected exptl. findings.
- 38Haase, M. F.; Brujic, J. Tailoring of High-Order Multiple Emulsions by the Liquid–Liquid Phase Separation of Ternary Mixtures. Angew. Chem., Int. Ed. 2014, 53, 11793– 11797, DOI: 10.1002/ANIE.201406040Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsV2nurbK&md5=cb3fe2c47478f50144005a43f02baff3Tailoring of High-Order Multiple Emulsions by the Liquid-Liquid Phase Separation of Ternary MixturesHaase, Martin F.; Brujic, JasnaAngewandte Chemie, International Edition (2014), 53 (44), 11793-11797CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors show that phase sepn. in emulsions having "onion" topol. occurs through self-similar cycles of mass transfer, spinodal decompn. or nucleation, and coalescence into multiple layers. Mapping out the phase diagram shows a linear relationship between the diams. of concentric layers, the slope of which depends on the initial ternary compn. and the mol. wt. of the surfactant. These general rules quant. predict the no. of droplet layers (multiplicity), which we used to devise self-assembly routes for polymer capsules and liposomes. This technique is extended to the assembly of lipid-stabilized droplets with ordered internal structures.
- 39Aveyard, R.; Binks, B. P.; Clint, J. H. Emulsions Stabilised Solely by Colloidal Particles. Adv. Colloid Interface Sci. 2003, 100–102, 503– 546, DOI: 10.1016/S0001-8686(02)00069-6Google Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXisVGmurY%253D&md5=4fd8d564819399175201c36b575eab2fEmulsions stabilised solely by colloidal particlesAveyard, Robert; Binks, Bernard P.; Clint, John H.Advances in Colloid and Interface Science (2003), 100-102 (), 503-546CODEN: ACISB9; ISSN:0001-8686. (Elsevier Science B.V.)A review. The prepn. and properties of emulsions, stabilized solely by the adsorption of solid particles at the oil-H2O interface, are reviewed esp. in the light of our own work with particles of well-controlled surface properties. Where appropriate, comparison is made with the behavior of surfactant-stabilized emulsions. Hydrophilic particles tend to form oil-in-H2O (o/w) emulsions whereas hydrophobic particles form H2O-in-oil (w/o) emulsions. Many of the properties can be attributed to the very large free energy of adsorption for particles of intermediate wettability (contact angle at the oil-H2O interface, for example, between 50 and 130°). This effectively irreversible adsorption leads to extreme stability for certain emulsions and is in contrast to the behavior of surfactant mols. which are usually in rapid dynamic equil. between the oil-H2O interface and the bulk phases. There is evidence that, in some systems, weak flocculation of the particles improves the emulsion stability. Phase inversion from w/o to o/w can be brought about by increasing the vol. fraction of H2O. Emulsions close to this inversion point tend to be the most stable, again in contrast to surfactant systems. The vol. fraction needed for inversion depends on the particle wettability and the nature of the oil and these effects were rationalized in terms of surface energy components. Stable multiple emulsions (w/o/w and o/w/o) can be made using 2 types of particles with slightly different wettability. Similar multiple emulsions prepd. with 2 types of surfactant tend to be much less stable. The possibility of prepg. novel solid materials by evapg. solid-stabilized emulsions is also proposed. Finally the authors report on some extensions to the work of Levine et al. who obtained expressions for the free energy of formation of emulsion drops covered with close-packed monolayers of monodisperse spherical particles. In particular in the light of the observations that nanoparticles can act as excellent emulsion stabilizers, the authors have considered potential effects on the free energy of emulsion formation of the action of small (phys. realistic) pos. and neg. line tensions in the 3-phase contact lines skirting particles adsorbed at the droplet interfaces. The authors also explore the possibility that curvature properties of close-packed particle monolayers can affect emulsion properties in much the same way that surfactant monolayer properties influence emulsion type and stability.
- 40Binks, B. P.; Rodrigues, J. A.; Frith, W. J. Synergistic Interaction in Emulsions Stabilized by a Mixture of Silica Nanoparticles and Cationic Surfactant. Langmuir 2007, 23, 3626– 3636, DOI: 10.1021/LA0634600Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhvF2qsLs%253D&md5=f6b810af0a248e114e458f69bf1641bfSynergistic Interaction in Emulsions Stabilized by a Mixture of Silica Nanoparticles and Cationic SurfactantBinks, Bernard P.; Rodrigues, Jhonny A.; Frith, William J.Langmuir (2007), 23 (7), 3626-3636CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Using a range of complementary expts., a detailed study into the behavior of dodecane-water emulsions stabilized by a mixt. of silica nanoparticles and pure cationic surfactant was made. Both emulsifiers prefer to stabilize o/w emulsions. At high pH, particles are ineffective emulsifiers, whereas surfactant-stabilized emulsions become increasingly stable to coalescence with concn. In mixts., no emulsion phase inversion occurs although synergism between the emulsifiers leads to enhanced stability at either fixed surfactant concn. or fixed particle concn. Emulsions are most stable under conditions where particles have negligible charge and are most flocculated. Freeze fracture SEM confirms the presence of particle flocs at drop interfaces. At low pH, particles and surfactant are good emulsifiers alone. Synergism is also displayed in these mixts., with the extent of creaming being min. when particles are most flocculated. Expts. were undertaken to offer an explanation for the latter synergy. By detg. the adsorption isotherm of surfactant on particles in water, we show that surfactant addn. initially leads to particle flocculation followed by re-dispersion. Using suitable contact angle measurements at oil-water-solid interfaces, we show that silica surfaces initially become increasingly hydrophobic upon surfactant addn., and surfactant adsorption lowering the oil-water interfacial tension. A competition exists between the influence of surfactant on the contact angle and the tension in the attachment energy of a particle to the interface.
- 41Fuerstenau, D. W.; Jia, R. The Adsorption of Alkylpyridinium Chlorides and their Effect on the Interfacial Behavior of Quartz. Colloids Surf., A 2004, 250, 223– 231, DOI: 10.1016/J.COLSURFA.2004.04.090Google Scholar41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVKlurjE&md5=ff8e8e13c90d30257fd05c09069b6244The adsorption of alkylpyridinium chlorides and their effect on the interfacial behavior of quartzFuerstenau, Douglas W.; Jia, RenheColloids and Surfaces, A: Physicochemical and Engineering Aspects (2004), 250 (1-3), 223-231CODEN: CPEAEH; ISSN:0927-7757. (Elsevier B.V.)This research was directed at understanding cationic surfactant adsorption phenomena on wet-ground natural quartz, mainly with dodecylpyridinium chloride as the model surfactant. How these surfactant ions adsorb at the interface was delineated through measurements of adsorption isotherms, zeta potentials, suspension stability, contact angles, induction times, and flotation response. Hydrocarbon chain assocn. of adsorbed surfactant ions (or self-assocn.) leads to 4 distinct adsorption regions as the concn. of surfactant is increased in soln. The same 4 regions manifest themselves in the behavior of all of the interfacial processes studied. At low concns., adsorption is controlled primarily by electrostatic interactions, but when the adsorbed surfactant ions begin to assoc. into hemimicelles at the surface, hydrophobic chain interactions control the adsorption process. The results of expts. with alkylpyridinium chlorides of 12, 14 and 16 C atoms can be normalized in terms of their CMCs, which clearly show that surface aggregation phenomena are driven by the same hydrophobic interactions that lead to micelle formation in bulk soln.
- 42Cui, Z. G.; Yang, L. L.; Cui, Y. Z.; Binks, B. P. Effects of Surfactant Structure on the Phase Inversion of Emulsions Stabilized by Mixtures of Silica Nanoparticles and Cationic Surfactant. Langmuir 2010, 26, 4717– 4724, DOI: 10.1021/LA903589EGoogle Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsV2nur3I&md5=f0db0d31a4f9a822022b484ba685d5f9Effects of Surfactant Structure on the Phase Inversion of Emulsions Stabilized by Mixtures of Silica Nanoparticles and Cationic SurfactantCui, Z.-G.; Yang, L.-L.; Cui, Y.-Z.; Binks, B. P.Langmuir (2010), 26 (7), 4717-4724CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Silica nanoparticles without any surface modification are not surface active at the toluene-water interface due to their extreme hydrophilicity but can be surface activated in situ by adsorbing cationic surfactant from water. This work studies the effects of the mol. structure of water-sol. cationic surfactant on the surface activation of the nanoparticles by emulsion characterization, adsorption and zeta potential measurements, dispersion stability expts., and detn. of relevant contact angles. An adsorbed cationic surfactant monolayer on particle surfaces is responsible for the wettability modification of the particles. In the presence of a trace amt. of cationic surfactant, the hydrophobicity of the particles increases, giving stable oil-in-water O/W(1) emulsions. At high surfactant concn. ( > cmc) the particle surface is retransformed to hydrophilic due to double-layer or hemimicelle formation, and the concn. of the free surfactant in the aq. phase is high enough to stabilize emulsions alone. O/W(2) emulsions, probably costabilized by free surfactant and particles, are then formed. The monolayer adsorption seems to be charge-site dependent. Thus, using single-chain trimethylammonium bromide surfactants or a double-head gemini cationic surfactant, the hydrophobicity of the particles achieved is not sufficient to stabilize water-in-oil (W/O) emulsions, and no phase inversion is induced. However, using a double-chain cationic surfactant, the chain d. on the particle surfaces endows them with a hydrophobicity high enough to stabilize W/O emulsions, and double phase inversion, O/W(1) → W/O → O/W(2), can then be achieved by increasing the surfactant concn.
- 43de Grooth, J.; Oborný, R.; Potreck, J.; Nijmeijer, K.; de Vos, W. M. The Role of Ionic Strength and Odd–Even Effects on the Properties of Polyelectrolyte Multilayer Nanofiltration Membranes. J. Membr. Sci. 2015, 475, 311– 319, DOI: 10.1016/J.MEMSCI.2014.10.044Google Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVGhsr3M&md5=b7bb87e7dee4eb462fc16697a5650ff5The role of ionic strength and odd-even effects on the properties of polyelectrolyte multilayer nanofiltration membranesde Grooth, Joris; Oborny, Radek; Potreck, Jens; Nijmeijer, Kitty; de Vos, Wiebe M.Journal of Membrane Science (2015), 475 (), 311-319CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)The modification of membranes by polyelectrolytes via the Layer-by-Layer technique is an attractive method to obtain nanofiltration membranes. We prep. such membranes by alternatively coating a polycation (poly(diallyldimethylammonium chloride) (PDADAMAC)) and a polyanion (poly(styrene sulfonate) (PSS)) on a porous support. Depending on the coating conditions, hollow fiber membranes with rejections of up to 71% NaCl and 96% Na2SO4 are obtained. Moreover, we demonstrate that the final membrane properties can be easily controlled by variation of the ionic strength of the coating soln., the no. of layers and the choice of terminating polyelectrolyte layer. Coating at higher salt concns. results in thicker multilayers that are more open to permeation. Furthermore, we show that by taking the effect of the terminating layer (the so called "odd-even" effect) into account, information on the structure of the multilayers on the membrane is obtained. Depending on the coating conditions and no. of layers, two different regimes can be distinguished. Thinner layers show a pore-dominated regime, where the multilayer is coated on the inside of the pores. Thicker layers show a layer-dominated regime, in which case the multilayer is predominately coated on top of the pores. This conclusion is supported by our ion rejection measurements: for thin layers the rejections are primarily based on size exclusion, whereas for thick layers the ion rejections are based on Donnan exclusion.
- 44McAloney, R. A.; Sinyor, M.; Dudnik, V.; Cynthia Goh, M. Atomic Force Microscopy Studies of Salt Effects on Polyelectrolyte Multilayer Film Morphology. Langmuir 2001, 17, 6655– 6663, DOI: 10.1021/LA010136QGoogle Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXms1Ont70%253D&md5=c3b5daf63884109f104ebe8fbb5ac7a9Atomic Force Microscopy Studies of Salt Effects on Polyelectrolyte Multilayer Film MorphologyMcAloney, Richard A.; Sinyor, Mark; Dudnik, Vyacheslav; Goh, M. CynthiaLangmuir (2001), 17 (21), 6655-6663CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The morphol. of multilayer films formed from poly(diallyldimethylammonium chloride) and poly(styrenesulfonic acid) deposited under a range of salt concns. (from 10-4 to 1.0 M) was investigated using at. force microscopy (AFM). Ten-bilayer films that were deposited with less than 0.3 M added NaCl were flat and featureless, with similar characteristics to the underlying silica substrate. When formed at and above this salt concn., a vermiculate morphol. was obsd. Thickness and roughness measurements were also carried out using the AFM and were found to increase with the concn. of added salt. The evolution of the vermiculate pattern was investigated by AFM studies of each layer that is deposited under high salt concn. (1.0 M NaCl). The first three bilayers were featureless and had a thickness of ∼6 nm/bilayer. A change in morphol. was obsd. by the fourth bilayer, and the av. thickness had increased to ∼46 nm/bilayer. These results may be explained in terms of a transition from an extended conformation to a more compact form that polyelectrolytes undergo as a function of the ionic strength of a soln.
- 45Goronja, J. M.; Janošević Ležaić, A. M.; Dimitrijević, B. M.; Malenović, A. M.; Stanisavljev, D. R.; Pejić, N. D. Determination of Critical Micelle Concentration of Cetyltrimethyl-Ammonium Bromide: Different Procedures for Analysis of Experimental Data. Chem. Ind. 2016, 70, 485– 492, DOI: 10.2298/HEMIND150622055GGoogle ScholarThere is no corresponding record for this reference.
- 46Miller, M. D.; Bruening, M. L. Correlation of the Swelling and Permeability of Polyelectrolyte Multilayer Films. Chem. Mater. 2005, 17, 5375– 5381, DOI: 10.1021/CM0512225Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVWhsLrO&md5=c7be8c8c98cc0f620cc806f7a151dfddCorrelation of the Swelling and Permeability of Polyelectrolyte Multilayer FilmsMiller, Matthew D.; Bruening, Merlin L.Chemistry of Materials (2005), 17 (21), 5375-5381CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)Alternating adsorption of polycations and polyanions on porous supports yields a variety of size-selective membranes whose swelling and transport properties depend on constituent polyelectrolytes, capping layer choice (polycation or polyanion), and deposition conditions. This report shows that in aq. expts., ellipsometrically detd. swelling percentages correlate well with nanofiltration (NF) rejections and diffusion dialysis fluxes. For example, hyaluronic acid (HA)/chitosan films swell 4 times more than poly(styrene sulfonate) (PSS)/poly(allylamine hydrochloride) coatings, and in NF expts., the HA/chitosan membranes permit a 250-fold greater fractional passage of sucrose. In general, films prepd. from polyelectrolytes with a high charge d. show low swelling and slow solute transport, presumably because of a high degree of ionic crosslinking. In the case of PSS/poly(diallyldimethylammonium chloride) (PDADMAC), PDADMAC-capped films can swell 4-fold more than their PSS-terminated counterparts, and as would be expected, glucose and sucrose transport rates in diffusion dialysis are about 1.7- and 17-fold more, resp., when these films end in PDADMAC. Polyelectrolyte multilayers also exhibit wide-ranging swelling properties in ethanol, but transport rates do not correlate with ethanol uptake. In this solvent, the d. of ionic cross-links and film hydrophobicity likely exert opposite effects on swelling, which could complicate the correlation between swelling and transport.
- 47Su, B.; Wang, T.; Wang, Z.; Gao, X.; Gao, C. Preparation and Performance of Dynamic Layer-by-Layer PDADMAC/PSS Nanofiltration Membrane. J. Membr. Sci. 2012, 423–424, 324– 331, DOI: 10.1016/J.MEMSCI.2012.08.041Google Scholar47https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFWit7bJ&md5=8e05da0d1c4d4551993e8d20ba51779cPreparation and performance of dynamic layer-by-layer PDADMAC/PSS nanofiltration membraneSu, Baowei; Wang, Tingting; Wang, Zongwen; Gao, Xueli; Gao, CongjieJournal of Membrane Science (2012), 423-424 (), 324-331CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Dynamic layer-by-layer (LBL) self-assembly technol. was used to prep. as few as three to five bilayers of poly(diallyl-dimethylammonium chloride) (PDADMAC) and poly(styrene sulfonate) (PSS) on neg. charged polysulfone (PS) ultrafiltration (UF) membranes of 50 kDa MWCO and compared with those of the static assembly membranes. The prepd. dynamic assembly (PDADMAC/PSS)4 nanofiltration (NF) membrane showed a permeation flux of 60 L m-2 h-1 at 1.0 MPa, much higher than that of the com. DL membrane (GE Osmonics, USA), but with a rejection of about 90% of SO42- which is relatively less than that of the DL membrane. The rejection performance showed that the dynamic-static assembly was more effective than others. Using dynamic-static assembly prepn., the rejection of (PDADMAC/PSS)3 membrane was about 90%, while the flux was about 55 L m-2 h-1 at 1.0 MPa. The surface morphol. of the prepd. LBL membranes were characterized by SEM and AFM, and no defect was found. The surface morphol. of the membrane prepd. by dynamic-static assembly was almost the same as the com. membranes. The anal. of filtration resistance indicated that the deposition of the first and second bilayer was crucial during the whole prepn. process.
- 48Notley, S. M.; Norgren, M. Adsorption of a Strong Polyelectrolyte to Model Lignin Surfaces. Biomacromolecules 2008, 9, 2081– 2086, DOI: 10.1021/BM800415UGoogle Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXns1elsbw%253D&md5=c063dac262d84bb440106b206ca29e1fAdsorption of a Strong Polyelectrolyte To Model Lignin SurfacesNotley, Shannon M.; Norgren, MagnusBiomacromolecules (2008), 9 (7), 2081-2086CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)The adsorption of a strong, highly charged cationic polyelectrolyte to a kraft lignin thin film was investigated as a function of the adsorbing soln. conditions using the quartz crystal microbalance. The polyelectrolyte, PDADMAC, with a mol. wt. of 100 kDa and one cationic charge group per monomer, was adsorbed to the anionically charged lignin film in the pH range 3.5-9.5 in electrolyte soln. of 0.1 to 100 mM NaCl. At low pH, the adsorbed amt. of PDADMAC was minimal, however, this increased as a function of increasing pH. Indeed, the surface excess increased significantly at about pH 8.5, where ionization of the phenolic groups on the lignin macromol. may be expected. Furthermore, at this elevated pH, the adsorbed amt. of PDADMAC decreased as the ionic strength of the soln. increased above 1 mM. This is due to the competitive adsorption of counterions to the lignin surface and indicates that the adsorption of PDADMAC to lignin is of a pure electrosorption nature.
- 49Bago Rodriguez, A. M.; Binks, B. P.; Sekine, T. Emulsions Stabilized with Polyelectrolyte Complexes Prepared from a Mixture of a Weak and a Strong Polyelectrolyte. Langmuir 2019, 35, 6693– 6707, DOI: 10.1021/ACS.LANGMUIR.9B00897Google Scholar49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXovVyrtrs%253D&md5=214411b64a3df371c530bd357c6f1685Emulsions Stabilized with Polyelectrolyte Complexes Prepared from a Mixture of a Weak and a Strong PolyelectrolyteBago Rodriguez, Ana Maria; Binks, Bernard P.; Sekine, TomokoLangmuir (2019), 35 (20), 6693-6707CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The possibility of stabilizing emulsions with polyelectrolyte complexes (PEC) obtained from the interaction of two non-surface-active oppositely charged polyelectrolytes (PEL) is described. Poly(allylamine hydrochloride) (PAH) and poly(4-styrene sulfonate) sodium salt are selected as the weak cationic and the strong anionic polyelectrolyte, resp. Aq. polymer mixts. are investigated by light scattering to det. the size of the complexes and whether pptn. or complex coacervation occurs. The effects of PEL mixing ratio, pH, and PEL concn. are studied in detail. By increasing the pH, the transition ppt.-ppt./coacervate-coacervate-polymer soln. is obsd. At low pH, both PEL are fully ionized and therefore ppts. (soft particles) arise as a result of strong electrostatic interactions. By increasing the pH, the degree of ionization of PAH decreases and weak electrostatic interactions ensue, supporting the formation of coacervate droplets. The most stable oil-in-water emulsions are prepd. from aq. mixts. around charge neutralization. Although emulsions can be prepd. from coacervate droplet dispersions, their coalescence stability is worse than those stabilized by soft PEC particles. By increasing the PEL concn., the av. droplet diam. decreases and the fraction of cream in the emulsion increases for emulsions prepd. with PEC particles, following the limited coalescence model. However, at high concns., emulsion stability is slightly worse probably due to extensive aggregation of the particles. Viscous high internal phase emulsions can be prepd. at low pH in which oil droplets are deformed. Here, PEC particles are detected only at the oil-water interface. At lower oil content, excess particles form a network in the aq. phase aiding emulsion stability to coalescence.
- 50Dodoo, S.; Balzer, B. N.; Hugel, T.; Laschewsky, A.; Von Klitzing, R. Effect of Ionic Strength and Layer Number on Swelling of Polyelectrolyte Multilayers in Water Vapour. Soft Mater. 2013, 11, 157– 164, DOI: 10.1080/1539445X.2011.607203Google Scholar50https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltlGhsw%253D%253D&md5=2c02a74fc44a95b0d531ec48c5db205cEffect of ionic strength and layer number on swelling of polyelectrolyte multilayers in water vaporDodoo, Samuel; Balzer, Bizan N.; Hugel, Thorsten; Laschewsky, Andre; von Klitzing, RegineSoft Materials (2013), 11 (2), 157-164CODEN: SMOAAE; ISSN:1539-445X. (Taylor & Francis, Inc.)The swelling behavior of polyelectrolyte multilayers (PEMs) of poly(sodium-4 styrene sulfonate) (PSS) and poly(diallyl di-Me ammonium chloride) (PDADMAC) prepd. from aq. soln. of 0.1 M and 0.5 M NaCl are investigated by ellipsometry and AFM. From 1 double-layer up to 4 double-layers of 0.1 M NaCl, the amt. of swelling water in the PEMs decreases with increasing no. of adsorbed double layers due to an increase in polyelectrolyte d. as a result of the attraction between the pos. charged outermost PDADMAC layer and the Si substrate. From 6 double layers to 30 double layers, the attraction is reduced due to a much larger distance between substrate and outermost layer leading to a much lower polyelectrolyte d. and higher swelling water. In PEMs prepd. from aq. soln. of 0.5 M NaCl, the amt. of water constantly increases which is related to a monotonically decreasing polyelectrolyte d. with increasing no. of polyelectrolyte layers. Studies of the surface topol. also indicate a transition from a more substrate affected interphase behavior to a continuum properties of the polyelectrolyte multilayers. The threshold for the transition from interphase to continuum behavior depends on the prepn. conditions of the PEM.
- 51Guzmán, E.; Ritacco, H.; Rubio, J. E. F.; Rubio, R. G.; Ortega, F. Salt-Induced Changes in the Growth of Polyelectrolyte Layers of Poly(diallyl-dimethylammonium chloride) and Poly(4-styrene sulfonate of sodium. Soft Matter 2009, 5, 2130– 2142, DOI: 10.1039/B901193EGoogle Scholar51https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXls1yrsr4%253D&md5=9eee5d2319ea5afec56547e634aa3f0eSalt-induced changes in the growth of polyelectrolyte layers of poly(diallyl-dimethylammonium chloride) and poly(4-styrene sulfonate of sodium)Guzman, Eduardo; Ritacco, Hernan; Rubio, Jose E. F.; Rubio, Ramon G.; Ortega, FranciscoSoft Matter (2009), 5 (10), 2130-2142CODEN: SMOABF; ISSN:1744-683X. (Royal Society of Chemistry)Multilayers formed by the sodium salt of poly(4-styrene sulfonate), PSS, and poly(diallyldimethylammonium) chloride, PDADMAC, have been built by electrostatic self-assembly from polyelectrolyte aq. solns. of different ionic strengths. The growth of the multilayers has been followed using dissipative quartz crystal microbalance and ellipsometry. Neutron reflectometry and XPS data indicate that the PSS and PDADMAC layers interpenetrate leading to an almost homogeneous polymer film. The results show that on increasing [NaCl] the growing process changes from a linear to a non-linear regime. The comparison of the thickness values obtained from QCM and ellipsometry has allowed us to calc. the water content of the polymer film. The results agree with those obtained by neutron reflectometry. The anal. of the QCM data has provided values of the complex shear modulus, which are typical of a rubber-like polymer system. The anal. of the mass adsorbed calcd. by the ellipsometry measurements indicated that the charge compensation mechanism changes from intrinsic at low ionic strengths to mainly extrinsic at high ionic strengths. Finally, it was found that the response of a polymer film to a change in [NaCl] is rather different for films grown at low or at high ionic strengths.
- 52Chen, Y.; Kim, S.; Cohen, Y. Tuning the Hydraulic Permeability and Molecular Weight Cutoff (MWCO) of Surface Nano-Structured Ultrafiltration Membranes. J. Membr. Sci. 2021, 629, 119180 DOI: 10.1016/J.MEMSCI.2021.119180Google Scholar52https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXotVWqsLY%253D&md5=d340358d1dc9355ccc5b7d9b306c4838Tuning the hydraulic permeability and molecular weight cutoff (MWCO) of surface nano-structured ultrafiltration membranesChen, Yian; Kim, Soomin; Cohen, YoramJournal of Membrane Science (2021), 629 (), 119180CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Hydraulic permeability and mol. wt. cutoff (MWCO) performance tuning of polysulfone (PSf) ultrafiltration (UF) membrane was attained via surface modification with a tethered layer of poly(acrylic acid) (PAA). Surface nano-structured (SNS) PAA layer was synthesized onto base PSf UF membranes by atm. pressure plasma (APP) surface activation followed by graft polymn. (GP) of acrylic acid (AA). Through a systematic study, it was shown that effective SNS-PAA-PSf UF membrane performance tuning was feasible by adjustments of APP and graft polymn. conditions. It was shown, for the first time, that SNS-PAA-PSf membranes can be synthesized with a range of hydraulic permeability (spanning a factor of 1.1-2.6 in magnitude) for a given MWCO, or a range of MWCO (spanning a factor of 1.5-2.3 in magnitude) for a given hydraulic permeability, thereby overcoming the hydraulic permeability-MWCO tradeoff.
- 53Crittenden, J. C.; Trussell, R. R.; Hand, D. W.; Howe, K. J.; Tchobanoglous, G. MWH’s Water Treatment. In Principles and Design, 3rd ed.; John Wiley & Sons, 2012.Google ScholarThere is no corresponding record for this reference.
- 54te Brinke, E.; Reurink, D. M.; Achterhuis, I.; de Grooth, J.; de Vos, W. M. Asymmetric Polyelectrolyte Multilayer Membranes with Ultrathin Separation Layers for Highly Efficient Micropollutant Removal. Appl. Mater. Today 2020, 18, 100471 DOI: 10.1016/J.APMT.2019.100471Google ScholarThere is no corresponding record for this reference.
- 55Daerr, A.; Mogne, A. Pendent_Drop: An ImageJ Plugin to Measure the Surface Tension from an Image of a Pendent Drop. J. Open Res. Softw. 2016, 4, 3, DOI: 10.5334/JORS.97Google ScholarThere is no corresponding record for this reference.
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- 4Shannon, M. A.; Bohn, P. W.; Elimelech, M.; Georgiadis, J. G.; Marĩas, B. J.; Mayes, A. M. Science and Technology for Water Purification in the Coming Decades. Nature 2008, 452, 301– 310, DOI: 10.1038/nature065994https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjsFCns7s%253D&md5=8eca80d34b155b0484e00fc8d32fcdb5Science and technology for water purification in the coming decadesShannon, Mark A.; Bohn, Paul W.; Elimelech, Menachem; Georgiadis, John G.; Marinas, Benito J.; Mayes, Anne M.Nature (London, United Kingdom) (2008), 452 (7185), 301-310CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)A review highlighting science and technol. being developed to improve water disinfection and decontamination and efforts to increase water supplies through safe re-use of wastewater and efficient desalination of seawater and brackish water is given. Topics discussed include: disinfection; decontamination; re-use and reclamation; desalination; and conclusions.
- 5Baig, M. I.; Pejman, M.; Willott, J. D.; Tiraferri, A.; de Vos, W. M. Polyelectrolyte Complex Hollow Fiber Membranes Prepared via Aqueous Phase Separation. ACS Appl. Polym. Mater. 2022, 4, 1010– 1020, DOI: 10.1021/ACSAPM.1C014645https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XmvFGguw%253D%253D&md5=47b421128a188b8ce7a10ad5426e70d7Polyelectrolyte Complex Hollow Fiber Membranes Prepared via Aqueous Phase SeparationBaig, Muhammad Irshad; Pejman, Mehdi; Willott, Joshua D.; Tiraferri, Alberto; de Vos, Wiebe M.ACS Applied Polymer Materials (2022), 4 (2), 1010-1020CODEN: AAPMCD; ISSN:2637-6105. (American Chemical Society)Hollow fiber (HF) membrane geometry is the preferred choice for most com. membrane operations. Such fibers are conventionally prepd. via the non-solvent-induced phase sepn. technique, which heavily relies on hazardous and reprotoxic org. solvents such as N-Me pyrrolidone. A more sustainable alternative, i.e., aq. phase sepn. (APS), was introduced recently that utilizes water as a solvent and non-solvent for the prodn. of polymeric membranes. Herein, for the first time, we demonstrate the prepn. of sustainable and functional HF membranes via the APS technique in a dry-jet wet spinning process. The dope soln. comprising poly(sodium 4-styrenesulfonate) (PSS) and polyethyleneimine (PEI) at high pH along with an aq. bore liq. is pushed through a single orifice spinneret into a low pH acetate buffer coagulation bath. Here, PEI becomes charged resulting in the formation of a polyelectrolyte complex with PSS. The compns. of the bore liq. and coagulation bath were systematically varied to study their effect on the structure and performance of the HF membranes. The microfiltration-type membranes (permeability ~ 500 to 800 L·m-2·h-1·bar-1) with complete retention of emulsion droplets were obtained when the pptn. rate was slow. Increasing the concn. of the acetate buffer in the bath led to the increase in pptn. rate resulting in ultrafiltration-type membranes (permeability ~ 12 to 15 L·m-2·h-1·bar-1) having mol. wt. cut-offs in the range of ~ 7.8-11.6 kDa. The research presented in this work confirms the versatility of APS and moves it another step closer to large-scale use.
- 6Reuvers, A. J.; Smolders, C. A. Formation of Membranes by Means of Immersion Precipitation: Part II. The Mechanism of Formation of Membranes Prepared from the System Cellulose Acetate-Acetone-Water. J. Membr. Sci. 1987, 34, 67– 86, DOI: 10.1016/S0376-7388(00)80021-66https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXjvFyktg%253D%253D&md5=8082c76cb213eff1782b4f0b7df4d3b8Formation of membranes by means of immersion precipitation. Part II. The mechanism of formation of membranes prepared from the system cellulose acetate-acetone-waterReuvers, A. J.; Smolders, C. A.Journal of Membrane Science (1987), 34 (1), 67-86CODEN: JMESDO; ISSN:0376-7388.Using equations and boundary conditions derived in an earlier paper, calcns. were performed on the ternary diffusion processes that occurs in a cellulose acetate (I)-acetone casting soln. immersed into a water bath. The necessary concn.-dependent thermodn. and hydrodynamic parameters were derived from exptl. data on the 3 limiting binary mixts. Calcns. show that immersion of the polymer soln. into the coagulation bath results in an instantaneous increase of the polymer concn. at the surface of the soln. For a I-acetone casting soln., the thickness of this concd. surface layer will increase until the onset of liq.-liq. demixing by means of nucleation and growth of the dild. phase that fixes the asym. polymer distribution in the film. The moment of onset of the demixing process depends on the thickness of the film. However, addn. of a certain min. amt. of water to the casting soln. results in an instantaneous onset of liq.-liq. demixing upon immersion, yielding a membrane with a very thin skin layer. The model calcns. were confirmed by light transmission measurements performed on immersed casting solns.
- 7Feng, C. Y.; Khulbe, K. C.; Matsuura, T.; Ismail, A. F. Recent Progresses in Polymeric Hollow Fiber Membrane Preparation, Characterization and Applications. Sep. Purif. Technol. 2013, 111, 43– 71, DOI: 10.1016/J.SEPPUR.2013.03.0177https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmsFCltLk%253D&md5=11398ec9dee5a88271742eadb7a4a9b5Recent progresses in polymeric hollow fiber membrane preparation, characterization and applicationsFeng, C. Y.; Khulbe, K. C.; Matsuura, T.; Ismail, A. F.Separation and Purification Technology (2013), 111 (), 43-71CODEN: SPUTFP; ISSN:1383-5866. (Elsevier B.V.)A review. Membrane sepn. using hollow fibers has become one of the emerging technologies which underwent a rapid growth during the past few decades. In this article, recent progresses (last 12 years) on polymeric hollow fiber membranes have been discussed. In particular, the following topics were identified as the recent trends in the hollow fiber research. Characterizations of membrane esp. by at. force microscopy (AFM) have been reported. New hollow fiber membranes for gas-sepn. have been developed. New polymers and techniques have been introduced in making high performance hollow fibers. Many PVDF based membranes have been developed. Orientation of polymer mol. during spinning was also investigated. However the mechanism of orientation is not fully investigated.
- 8Johnson, D. J.; Hilal, N. Nanocomposite Nanofiltration Membranes: State of Play and Recent Advances. Desalination 2022, 524, 115480 DOI: 10.1016/J.DESAL.2021.1154808https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXis1GjtLfO&md5=4eec0df4c50d27ff6fab4400d87a5791Nanocomposite nanofiltration membranes: State of play and recent advancesJohnson, Daniel James; Hilal, NidalDesalination (2022), 524 (), 115480CODEN: DSLNAH; ISSN:0011-9164. (Elsevier B.V.)A review. Much research has been carried out in recent years to investigate the use of nanomaterials as fillers in polymeric nanofiltration membranes, to improve water transport and fouling resistance while preserving, where possible, selectivity. This review paper considers the background to this research, including membrane fabrication and incorporation of various nanomaterials and the addnl. functionalities achieved by nanomaterial incorporation, followed by a crit. review of the recent literature in this area. The research efforts which have accumulated in recent years shows great promise for improving the transport and fouling properties of NF membranes for a variety of applications, but this field is still immature and shows much room for further research. Despite this, caution must be made to ensure that research is focussed on practical solns., capable of being scaled up within com. acceptable constraints.
- 9Yang, Z.; Sun, P.-F.; Li, X.; Gan, B.; Wang, L.; Song, X.; Park, H.-D.; Tang, C. Y. A Critical Review on Thin-Film Nanocomposite Membranes with Interlayered Structure: Mechanisms, Recent Developments, and Environmental Applications. Environ. Sci. Technol. 2020, 54, 15563– 15583, DOI: 10.1021/ACS.EST.0C053779https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXitlOntr3K&md5=cbb3d18a7c73091e353be08e0d58edf2A Critical Review on Thin-Film Nanocomposite Membranes with Interlayered Structure: Mechanisms, Recent Developments, and Environmental ApplicationsYang, Zhe; Sun, Peng-Fei; Li, Xianhui; Gan, Bowen; Wang, Li; Song, Xiaoxiao; Park, Hee-Deung; Tang, Chuyang Y.Environmental Science & Technology (2020), 54 (24), 15563-15583CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)A review. The sepn. properties of polyamide reverse osmosis and nanofiltration membranes, widely applied for desalination and water reuse, are constrained by the permeability-selectivity upper bound. Although thin-film nanocomposite (TFN) membranes incorporating nanomaterials exhibit enhanced water permeance, their rejection is only moderately improved or even impaired due to agglomeration of nanomaterials and formation of defects. A novel type of TFN membranes featuring an interlayer of nanomaterials (TFNi) has emerged in recent years. These novel TFNi membranes show extraordinary improvement in water flux (e.g., up to an order of magnitude enhancement) along with better selectivity. Such enhancements can be achieved by a wide selection of nanomaterials, ranging from nanoparticles, one-/two-dimensional materials, to interfacial coatings. The use of nanostructured interlayers not only improves the formation of polyamide rejection layers but also provides an optimized water transport path, which enables TFNi membranes to potentially overcome the longstanding trade-off between membrane permeability and selectivity. Furthermore, TFNi membranes can potentially enhance the removal of heavy metals and micropollutants, which is crit. for many environmental applications. This review critically examines the recent developments of TFNi membranes and discusses the underlying mechanisms and design criteria. Their potential environmental applications are also highlighted.
- 10Zodrow, K.; Brunet, L.; Mahendra, S.; Li, D.; Zhang, A.; Li, Q.; Alvarez, P. J. J. Polysulfone Ultrafiltration Membranes Impregnated with Silver Nanoparticles Show Improved Biofouling Resistance and Virus Removal. Water Res. 2009, 43, 715– 723, DOI: 10.1016/J.WATRES.2008.11.01410https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFelsb8%253D&md5=ec610b7c06515992084af9ada3d0259dPolysulfone ultrafiltration membranes impregnated with silver nanoparticles show improved biofouling resistance and virus removalZodrow, Katherine; Brunet, Lena; Mahendra, Shaily; Li, Dong; Zhang, Anna; Li, Qilin; Alvarez, Pedro J. J.Water Research (2009), 43 (3), 715-723CODEN: WATRAG; ISSN:0043-1354. (Elsevier Ltd.)Biofouling and virus penetration are two significant obstacles in water treatment membrane filtration. Biofouling reduces membrane permeability, increases energy costs, and decreases the lifetime of membranes. In order to effectively remove viruses, nanofiltration or reverse osmosis (both high energy filtration schemes) must be used. Thus, there is an urgent demand for low pressure membranes with anti-biofouling and antiviral properties. The antibacterial properties of silver are well known, and silver nanoparticles (nAg) are now incorporated into a wide variety of consumer products for microbial control. In this study, nAg incorporated into polysulfone ultrafiltration membranes (nAg-PSf) exhibited antimicrobial properties towards a variety of bacteria, including Escherichia coli K12 and Pseudomonas mendocina KR1, and the MS2 bacteriophage. Nanosilver incorporation also increased membrane hydrophilicity, reducing the potential for other types of membrane fouling. XPS anal. indicated a significant loss of silver from the membrane surface after a relatively short filtration period (0.4 L/cm2) even though ICP anal. of digested membrane material showed that 90% of the added silver remained in the membrane. This silver loss resulted in a significant loss of antibacterial and antiviral activity. Thus, successful fabrication of nAg-impregnated membranes needs to allow for the release of sufficient silver ions for microbial control while preventing a rapid depletion of silver.
- 11Ben-Sasson, M.; Zodrow, K. R.; Genggeng, Q.; Kang, Y.; Giannelis, E. P.; Elimelech, M. Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface Properties. Environ. Sci. Technol. 2014, 48, 384– 393, DOI: 10.1021/ES404232S11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvV2mt7nI&md5=b613e4793a3364a0a1c22707a9c1f3d6Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface PropertiesBen-Sasson, Moshe; Zodrow, Katherine R.; Genggeng, Qi; Kang, Yan; Giannelis, Emmanuel P.; Elimelech, MenachemEnvironmental Science & Technology (2014), 48 (1), 384-393CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)Biofouling is a major operational challenge in reverse osmosis (RO) desalination, motivating a search for improved biofouling control strategies. Copper, long known for its antibacterial activity and relatively low cost, is an attractive potential biocidal agent. The authors present a method for loading copper nanoparticles (Cu-NPs) on the surface of a thin-film composite (TFC) polyamide RO membrane. Cu-NPs were synthesized using polyethyleneimine (PEI) as a capping agent, resulting in particles with an av. radius of 34 nm and a copper content between 39 and 49%. The pos. charge of the Cu-NPs imparted by the PEI allowed a simple electrostatic functionalization of the neg. charged RO membrane. The authors confirmed functionalization and irreversible binding of the Cu-NPs to the membrane surface with SEM and XPS after exposing the membrane to bath sonication. Also Cu-NP functionalization can be repeated after the Cu-NPs dissolve from the membrane surface. The Cu-NP functionalization had minimal impact on the intrinsic membrane transport parameters. Surface hydrophilicity and surface roughness were also maintained, and the membrane surface charge became pos. after functionalization. The functionalized membrane exhibited significant antibacterial activity, leading to an 80-95% redn. in the no. of attached live bacteria for three different model bacterial strains. Challenges assocd. with this functionalization method and its implementation in RO desalination are discussed.
- 12Alhoshan, M.; Alam, J.; Dass, L. A.; Al-Homaidi, N. Fabrication of Polysulfone/ZnO Membrane: Influence of ZnO Nanoparticles on Membrane Characteristics. Adv. Polym. Technol. 2013, 32, 21369 DOI: 10.1002/ADV.2136912https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1Shs7bM&md5=52410d2ffc0d1d6c2b2d1d4999dc7f00Fabrication of Polysulfone/ZnO Membrane: Influence of ZnO Nanoparticles on Membrane CharacteristicsAlhoshan, Mansour; Alam, Javed; Dass, Lawrence Arockiasamy; Al-Homaidi, NasserAdvances in Polymer Technology (2013), 32 (4), 21369/1-21369/7CODEN: APTYD5; ISSN:0730-6679. (John Wiley & Sons, Inc.)A mixed matrix membrane consisting of a polysulfone and nano-ZnO particles has been fabricated by a combination of soln. dispersion blending and phase-inversion method. The study is focused on the influence of ZnO on membrane morphol., surface roughness, and hydrophilicity, which were investigated through the methods of SEM, at. force microscopy, and contact angle meter, resp. In addn., the changes in membrane characteristics with the addn. nano-ZnO particles were examd. by pure water flux, water content and porosity, and salts rejection including NaCl and MgSO4. From the results, it was revealed that nano-ZnO particles constructed a membrane having more hydrophilic, smooth, and tightly packed surface, which offered a high flux and an effective permeability barrier. Moreover, it was obsd. that nano-ZnO particles produced spongy a membrane with uniform and well-interconnecting pores. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21369; View this article online at wileyonlinelibrary. com. DOI 10.1002/adv.21369.
- 13Escobar-Ferrand, L.; Li, D.; Lee, D.; Durning, C. J. All-Nanoparticle Layer-by-Layer Surface Modification of Micro- and Ultrafiltration Membranes. Langmuir 2014, 30, 5545– 5556, DOI: 10.1021/LA500248913https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtV2rtrc%253D&md5=84ca0afad4f5f2381e445b1068a10377All-Nanoparticle Layer-by-Layer Surface Modification of Micro- and Ultrafiltration MembranesEscobar-Ferrand, Luis; Li, Diya; Lee, Daeyeon; Durning, Christopher J.Langmuir (2014), 30 (19), 5545-5556CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Layer-by-layer (LbL) deposition using primarily inorg. silica nanoparticles is employed for surface modification of polymeric micro- and ultrafiltration (MF/UF) membranes to produce novel thin film composite (TFC) membranes intended for nanofiltration (NF) and reverse osmosis (RO) applications. A wide variety of porous substrate membranes with different surface characteristics are successfully employed. This report gives detailed results for polycarbonate track etched (PCTE), polyethersulfone (PES), and sulfonated PES (SPEES) MF/UF substrates. Both spherical (cationic/anionic) and eccentric elongated (anionic) silica nanoparticles are deposited using conditions similar to those in prior works for solid substrates (e.g., Lee et al.). Appropriate selection of the pH for anionic and cationic particle deposition enables construction of nanoparticle-only layers 100-1200 nm in thickness atop the original porous membrane substrates. The surface layer thickness appears to vary linearly with the no. of bilayers deposited, i.e., with the no. of anionic/cationic deposition cycles. The deposition process is optimized to eliminate drying-induced cracking and improve mech. durability via thickness control and postdeposition hydrothermal treatment. Dead-end permeation tests using dextran stds. reveal the hydraulic characteristics and sepns. capability for the PCTE-based TFC membranes. Nanoparticle-based LbL surface modification of MF and UF rated media can produce TFC membranes with NF capabilities.
- 14Soroko, I.; Livingston, A. Impact of TiO2 Nanoparticles on Morphology and Performance of Crosslinked Polyimide Organic Solvent Nanofiltration (OSN) Membranes. J. Membr. Sci. 2009, 343, 189– 198, DOI: 10.1016/J.MEMSCI.2009.07.02614https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVOis7zF&md5=d824fcf2de2d42dcbe7920abeff035a6Impact of TiO2 nanoparticles on morphology and performance of crosslinked polyimide organic solvent nanofiltration (OSN) membranesSoroko, Iwona; Livingston, AndrewJournal of Membrane Science (2009), 343 (1-2), 189-198CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Chem. crosslinked polyimide org.-inorg. composite nanofiltration membranes suitable for application in harsh org. solvents were successfully prepd. by phase inversion of dope solns. TiO2 nanoparticles were dispersed in these dope solns., comprising polyimide (PI) in N,N-dimethylformamide/1,4-dioxane. The impact of TiO2 on the resulting PI membranes was studied using SEM, TGA, water contact angle, dope viscosity measurements and mech. strength. The presence of TiO2 nanoparticles within the membrane matrix was proved by the detection of a peak characteristic of TiO2 in the WAXS pattern. SEM pictures of the cross-section of the PI/TiO2 membranes showed dramatically changed morphol. compared to ref. membranes with no TiO2 addn. Macrovoids present in ref. membranes were suppressed by increasing loading of TiO2 nanoparticles, and eventually disappeared completely at a TiO2 loading above 3 wt.%. Decreasing water contact angle and an increase in ethanol flux indicated that hydrophilicity increased as nanoparticle loading increased. The effect of TiO2 on the functional performance of the membranes was evaluated by measuring flux and rejection using cross-flow filtration. Perhaps surprisingly, the presence of TiO2 improved the compaction resistance of the membranes, whereas rejection and steady flux were almost unaltered.
- 15Sun, M.; Su, Y.; Mu, C.; Jiang, Z. Improved Antifouling Property of PES Ultrafiltration Membranes Using Additive of Silica-PVP Nanocomposite. Ind. Eng. Chem. Res. 2010, 49, 790– 796, DOI: 10.1021/IE900560E15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsV2nur3M&md5=f6475ea6238374c4c9d7367a5e97660fImproved Antifouling Property of PES Ultrafiltration Membranes using Additive of Silica-PVP NanocompositeSun, Meng-Ping; Su, Yan-Lei; Mu, Chun-Xia; Jiang, Zhong-YiIndustrial & Engineering Chemistry Research (2010), 49 (2), 790-796CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)To improve the surface coverage of polyvinylpyrrolidone (PVP) on membrane surfaces and further enhance the antifouling property, a silica-PVP nanocomposite was synthesized and used as a novel hydrophilic additive to modify polyethersulfone (PES) membranes. Transmission electron microscopy (TEM) observation showed that PES membranes, using additives of PVP and silica-PVP nanocomposites, have similar asym. structures. XPS measurement indicated that the near-surface coverage of PVP for PES membrane with a silica-PVP nanocomposite additive is greater than that with a PVP additive. Protein ultrafiltration expt. also showed that the antifouling ability of PES membrane with a silica-PVP nanocomposite additive is stronger than that with a PVP additive. The hydrophilic modification with a silica-PVP nanocomposite is an appropriate method for improved antifouling property of PES ultrafiltration membranes.
- 16Haase, M. F.; Jeon, H.; Hough, N.; Kim, J. H.; Stebe, K. J.; Lee, D. Multifunctional Nanocomposite Hollow Fiber Membranes by Solvent Transfer Induced Phase Separation. Nat. Commun. 2017, 8, 1234 DOI: 10.1038/s41467-017-01409-316https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M7msVSisQ%253D%253D&md5=e6ab18c5803bd8cb0852a426240e10a7Multifunctional nanocomposite hollow fiber membranes by solvent transfer induced phase separationHaase Martin F; Hough Noah; Jeon Harim; Stebe Kathleen J; Lee Daeyeon; Jeon Harim; Kim Jong HakNature communications (2017), 8 (1), 1234 ISSN:.The decoration of porous membranes with a dense layer of nanoparticles imparts useful functionality and can enhance membrane separation and anti-fouling properties. However, manufacturing of nanoparticle-coated membranes requires multiple steps and tedious processing. Here, we introduce a facile single-step method in which bicontinuous interfacially jammed emulsions are used to form nanoparticle-functionalized hollow fiber membranes. The resulting nanocomposite membranes prepared via solvent transfer-induced phase separation and photopolymerization have exceptionally high nanoparticle loadings (up to 50 wt% silica nanoparticles) and feature densely packed nanoparticles uniformly distributed over the entire membrane surfaces. These structurally well-defined, asymmetric membranes facilitate control over membrane flux and selectivity, enable the formation of stimuli responsive hydrogel nanocomposite membranes, and can be easily modified to introduce antifouling features. This approach forms a foundation for the formation of advanced nanocomposite membranes comprising diverse building blocks with potential applications in water treatment, industrial separations and as catalytic membrane reactors.
- 17Haase, M. F.; Stebe, K. J.; Lee, D. Continuous Fabrication of Hierarchical and Asymmetric Bijel Microparticles, Fibers, and Membranes by Solvent Transfer-Induced Phase Separation (STRIPS). Adv. Mater. 2015, 27, 7065– 7071, DOI: 10.1002/ADMA.20150350917https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1Slu77I&md5=e4f4ae7858d773078101d6c7dbf657a2Continuous Fabrication of Hierarchical and Asymmetric Bijel Microparticles, Fibers, and Membranes by Solvent Transfer-Induced Phase Separation (STRIPS)Haase, Martin F.; Stebe, Kathleen J.; Lee, DaeyeonAdvanced Materials (Weinheim, Germany) (2015), 27 (44), 7065-7071CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A scalable method for continuous fabrication of hierarchically and asym. structured bijel microparticles, fibers, and membranes via STRIPS using ternary liq. mixts. is presented. The resulting fibers are indeed bicontinuous as demonstrated by the transport of mols. of differing polarity within the structure. STRIPS provides several advantages that make it a highly translatable technique for bijel formation. Compared to the conventional method that uses binary liq. mixts., wide varieties of immiscible liq. combinations can be used for bijel prepn. The fast quenching of the ternary mixt. by STRIPS allows for the formation of hierarchical and asym. microstructures with submicron features, which expands the potential of bijels in various applications.
- 18Park, T.; Choi, G. H.; Lee, D.; Yoo, P. Y. Metal-Phenolic Network-Coated Hollow Fiber Catalytic Membranes via Solvent Transfer Induced Phase Separation (STRIPS) for Suzuki Coupling Reaction. J. Membr. Sci. 2021, 634, 119386 DOI: 10.1016/J.MEMSCI.2021.11938618https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtFSgs7%252FO&md5=2688d0776b63a4dd30f9ca3828d1f0c2Metal-phenolic network-coated hollow fiber catalytic membranes via solvent transfer induced phase separation (STRIPS) for Suzuki coupling reactionPark, Taejung; Choi, Gwan H.; Lee, Daeyeon; Yoo, Pil J.Journal of Membrane Science (2021), 634 (), 119386CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Catalytically reactive membranes enable continuous and high yield chem. reactions while obviating the need for catalyst sepn. from the product stream. Despite recent advances, there still exists considerable challenges in developing high performance catalytic membranes. Most works to date have used planar membranes made of chem. inert materials, limiting conversion efficiency due to their low sp. surface area and difficulty assocd. with incorporating a high d. of catalytic nanoparticles on their surface. To overcome these limitations, we employ a single-step solvent transfer-induced phase sepn. (STRIPS) method to prep. nanocomposite hollow fiber membranes. Taking advantage of a dense layer of silica nanoparticles (NPs) on the surface of the STRIPS membrane, catalytic activity is imbued by coating the membrane surface with palladium (Pd)-supported metal-phenolic network (MPN). These catalytic hollow fiber membranes are used to perform Suzuki-Miyaura cross-coupling reactions, enabling continuous prodn. of biaryl compds. with a high conversion efficiency (>90%) while retaining high permeability (>60 L/m2·h (LMH) at 1 bar-pressurized condition). The approach presented in this work synergistically combines hollow fiber nanocomposite structures and MPN coating to offer a versatile platform for developing the next generation reactive membranes for synthesizing valuable chems.
- 19Tran, L.; Haase, M. F. Templating Interfacial Nanoparticle Assemblies via in Situ Techniques. Langmuir 2019, 35, 8584– 8602, DOI: 10.1021/ACS.LANGMUIR.9B0013019https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXjvVyks78%253D&md5=ba94c2cf4698c0a2c5ae6631733ebe95Templating Interfacial Nanoparticle Assemblies via in Situ TechniquesTran, Lisa; Haase, Martin F.Langmuir (2019), 35 (26), 8584-8602CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)A review. In situ surface modification of nanoparticles has a rich industrial history, but in recent years, it has also received increased attention in the field of directed self-assembly. In situ techniques rely on components within a Pickering emulsion system, such as amphiphiles that act as hydrophobizers or ionic species that screen charges, to drive the interfacial assembly of particles. Instead of stepwise procedures to chem. tune the particle wettability, in situ methods use elements already present within the system to alter the nanoparticle interfacial behavior, often depending on Coulombic interactions to simplify operations. The surface modifications are not contingent on specific chem. reactions, which further enables a multitude of possible nanoparticles to be used within a given system. In recent studies, in situ methods have been combined with external means of shaping the interface to produce materials with high interfacial areas and complex geometries. These systems have facilely tunable properties, enabling their use in an extensive array of applications. In this feature article, in honor of the late Prof. Helmuth M.ovrddot.ohwald, we review how in situ techniques have influenced the development of soft, advanced materials, covering the fundamental interfacial phenomena with an outlook on materials science.
- 20Boakye-Ansah, S.; Schwenger, M. S.; Haase, M. F. Designing Bijels Formed by Solvent Transfer Induced Phase Separation with Functional Nanoparticles. Soft Matter 2019, 15, 3379– 3388, DOI: 10.1039/C9SM00289H20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlvVWrs78%253D&md5=628c88c62d2902c72addcc35b9d5dd25Designing bijels formed by solvent transfer induced phase separation with functional nanoparticlesBoakye-Ansah, Stephen; Schwenger, Matthew S.; Haase, Martin F.Soft Matter (2019), 15 (16), 3379-3388CODEN: SMOABF; ISSN:1744-6848. (Royal Society of Chemistry)Bicontinuous interfacially jammed emulsion gels (bijels) formed via solvent transfer induced phase sepn. (STrIPS) are new soft materials with potential applications in sepns., healthcare, or catalysis. To facilitate their applications, means to fabricate STrIPS bijels with nanoparticles of various surface chemistries are needed. Here, we investigate the formation of STrIPS bijels with nanoparticles of different wettabilities, ranging from partially hydrophobic to extremely hydrophilic. To this end, the surface wettability of silica nanoparticles is tailored by functionalization with ligands bearing either hydrophobic or hydrophilic terminal groups. We show that partially hydrophobic particles with acrylate groups can impart short-term stability to STrIPS bijels on their own. However, to enable long-term stability, the use of cationic surfactants is needed. Partially hydrophobic particles require short chain surfactants for morphol. stability while glycerol-functionalized hydrophilic particles require double chain cationic surfactants. Variation of the surfactant concn. results in various STrIPS bijel morphologies with controllable domain sizes. Last, we show that functional groups on the nanoparticles facilitate interfacial crosslinking for the purposes of reinforcing STrIPS bijels. Our research lays the foundation for the use of a wide variety of solid particles, irresp. of their surface wettabilities, to fabricate bijels with potential applications in Pickering interfacial catalysis and as cross-flow microreactors.
- 21Boakye-Ansah, S.; Khan, M. A.; Haase, M. F. Controlling Surfactant Adsorption on Highly Charged Nanoparticles to Stabilize Bijels. J. Phys. Chem. C 2020, 124, 12417– 12423, DOI: 10.1021/ACS.JPCC.0C0144021https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXpt1Olt7w%253D&md5=15ad6c3c07a7e4d1cff8de7a8c830d6cControlling Surfactant Adsorption on Highly Charged Nanoparticles to Stabilize BijelsBoakye-Ansah, Stephen; Khan, Mohd Azeem; Haase, Martin F.Journal of Physical Chemistry C (2020), 124 (23), 12417-12423CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Bicontinuous particle-stabilized emulsions (bijels) are networks of interpenetrating oil/water channels with applications in catalysis, tissue engineering, and energy storage. Bijels can be generated by arresting solvent transfer induced phase sepn. (STrIPS) via interfacial jamming of nanoparticles. However, until now, STrIPS bijels have only been formed with silica nanoparticles of low surface charge densities, limiting their potential applications in catalysis and fluid transport. Here, we show how strongly charged silica nanoparticles can stabilize bijels. To this end, we carry out a systematic study employing dynamic light scattering, zeta potential, acid/base titrns., turbidimetry, surface tension, and confocal microscopy. We find that moderating the adsorption of oppositely charged surfactants on the particles is crucial to facilitate particle dispersibility in the bijel casting mixt. and bijel stabilization. Our results potentially introduce a general understanding for bijel fabrication with different inorg. nanoparticle materials of variable charge d.
- 22Khan, M. A.; Sprockel, A. J.; Macmillan, K. A.; Alting, M. T.; Kharal, S. P.; Boakye-Ansah, S.; Haase, M. F. Nanostructured, Fluid-Bicontinuous Gels for Continuous-Flow Liquid-Liquid Extraction. Adv. Mater. 2022, 34, 2109547 DOI: 10.1002/ADMA.20210954722https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XovVyqurY%253D&md5=4f69a400e6aab88bcb4f615555d98ff9Nanostructured, Fluid-Bicontinuous Gels for Continuous-Flow Liquid-Liquid ExtractionKhan, Mohd A.; Sprockel, Alessio J.; Macmillan, Katherine A.; Alting, Meyer T.; Kharal, Shankar P.; Boakye-Ansah, Stephen; Haase, Martin F.Advanced Materials (Weinheim, Germany) (2022), 34 (18), 2109547CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)Fluid-bicontinuous gels are unique materials that allow two distinct fluids to interact through a percolating, rigid scaffold. Current restrictions for their use are the large fluid-channel sizes (>5 μm), limiting the fluid-fluid interaction surface-area, and the inability to flow liqs. through the channels. In this work a scalable synthesis route of nanoparticle stabilized fluid-bicontinuous gels with channels sizes below 500 nm and sp. surface areas of 2 m2 cm-3 is introduced. Moreover, it is demonstrated that liqs. can be pumped through the fluid-bicontinuous gels via electroosmosis. The fast liq. flow in the fluid-bicontinuous gel facilitates their use for mol. sepns. in continuous-flow liq.-liq. extn. Together with the high surface areas, liq. flow through fluid-bicontinuous gels enhances their potential as highly permeable porous materials with possible uses as microreaction media, fuel-cell components, and sepn. membranes.
- 23Kharal, S. P.; Haase, M. F. Centrifugal Assembly of Helical Bijel Fibers for pH Responsive Composite Hydrogels. Small 2022, 18, 2106826 DOI: 10.1002/SMLL.20210682623https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhslCgsrY%253D&md5=7b8db2761549fff0d8c4f9b1c5861aa0Centrifugal Assembly of Helical Bijel Fibers for pH Responsive Composite HydrogelsKharal, Shankar P.; Haase, Martin F.Small (2022), 18 (11), 2106826CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)In microfluidics, centrifugal forces are important for centrifugal microfluidic chips and curved microchannels. Here, an unrecognized use of the centrifugal effect in microfluidics is introduced. The assembly of helical soft matter fibers in a rotating microcapillary is investigated. During assembly, the fibers undergo phase sepn., generating particle stabilized bicontinuous interfacially jammed emulsions gels. This process is accompanied by a transition of the fiber d. over time. As a result, the direction of the centrifugal force in the rotating microcapillary changes. The authors analyze this effect systematically with high-speed video microscopy and complementary computer simulations. The resulting understanding enables the control of the helical fiber assembly into microropes. These microropes can be converted into pH responsive hydrogels that swell and shrink with potential applications in tissue engineering, soft robotics, controlled release, and sensing. More generally, the knowledge gained from this work shows that centrifugal forces potentially enable directed self-assembly or sepn. of colloids, biol. cells, and emulsions in microfluidics.
- 24Kharal, S. P.; Hesketh, R. P.; Haase, M. F. High-Tensile Strength, Composite Bijels through Microfluidic Twisting. Adv. Funct. Mater. 2020, 30, 2003555 DOI: 10.1002/ADFM.20200355524https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlegtbrP&md5=e718279cc3859cf90fbd145e89a3d2afHigh-Tensile Strength, Composite Bijels through Microfluidic TwistingKharal, Shankar P.; Hesketh, Robert P.; Haase, Martin F.Advanced Functional Materials (2020), 30 (35), 2003555CODEN: AFMDC6; ISSN:1616-301X. (Wiley-VCH Verlag GmbH & Co. KGaA)Rope making is a millennia old technique to collectively assemble numerous weak filaments into flexible and high tensile strength bundles. However, delicate soft matter fibers lack the robustness to be twisted into bundles by means of mech. rope making tools. Here, weak microfibers with tensile strengths of a few kilopascals are combined into ropes via microfluidic twisting. This is demonstrated for recently introduced fibers made of bicontinuous interfacially jammed emulsion gels (bijels). Bijels show promising applications in use as membranes, microreactors, energy and healthcare materials, but their low tensile strength make reinforcement strategies imperative. Hydrodynamic twisting allows to produce continuous bijel fiber bundles of controllable architecture. Modeling the fluid flow field reveals the bundle geometry dependence on a subtle force balance composed of rotational and translational shear stresses. Moreover, combining multiple bijel fibers of different compns. enables the introduction of polymeric support fibers to raise the tensile strength to tens of megapascals, while simultaneously preserving the liq. like properties of the bijel fibers for transport applications. Hydrodynamic twisting shows potentials to enable the combination of a wide range of materials resulting in composites with features greater than the sum of their parts.
- 25Joseph, N.; Ahmadiannamini, P.; Hoogenboom, R.; Vankelecom, I. F. J. Layer-by-Layer Preparation of Polyelectrolyte Multilayer Membranes for Separation. Polym. Chem. 2014, 5, 1817– 1831, DOI: 10.1039/C3PY01262J25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXivFWqsb4%253D&md5=0972319234c36e7e354f7eea766b8a6eLayer-by-layer preparation of polyelectrolyte multilayer membranes for separationJoseph, Nithya; Ahmadiannamini, Pejman; Hoogenboom, Richard; Vankelecom, Ivo. F. J.Polymer Chemistry (2014), 5 (6), 1817-1831CODEN: PCOHC2; ISSN:1759-9962. (Royal Society of Chemistry)A review. Polymer membranes provide a highly promising platform for the development of an efficient and sustainable technique for sepn. Ideally such membranes combine a high flux with a high selectivity requiring thin defect-free membranes. The layer by layer (LBL) assembly technique has proven to be a versatile and simple method for the fabrication of very thin polyelectrolyte multilayers making it highly suitable for the prepn. of sepn. membranes. Recent developments in this field related to membrane prepn. and their applications in sepn. processes are presented and discussed in this review. An overview of the different fabrication techniques of such membranes will be first provided. In addn., the formation mechanism and the parameters that can be varied to tune the properties of the membranes will be discussed. Finally, the potential applications of these membranes in different sepn. areas such as pervaporation, nanofiltration, solvent resistant nanofiltration, reverse osmosis, gas sepn. and forward osmosis will be addressed.
- 26Reurink, D. M.; Willott, J. D.; Roesink, H. D. W.; de Vos, W. M. Role of Polycation and Cross-Linking in Polyelectrolyte Multilayer Membranes. ACS Appl. Polym. Mater. 2020, 2, 5278– 5289, DOI: 10.1021/ACSAPM.0C0099226https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXit1arsb3M&md5=aed37b3ce6129721152a2b61eb9d5fecRole of Polycation and Cross-Linking in Polyelectrolyte Multilayer MembranesReurink, D. M.; Willott, J. D.; Roesink, H. D. W.; de Vos, W. M.ACS Applied Polymer Materials (2020), 2 (11), 5278-5289CODEN: AAPMCD; ISSN:2637-6105. (American Chemical Society)Alternate deposition of oppositely charged polyelectrolytes is an excellent approach to control the chem. of interfaces. Membrane technol. is one field that benefits from the simplicity and tunability of polyelectrolyte multilayers (PEMs). Herein, ultrafiltration support membranes are coated with PEMs to fabricate nanofiltration membranes. Three PEMs, of different polymeric structures, namely, those of poly(4-styrene sulfonate) (PSS)/poly(allylamine hydrochloric acid) (PAH), PSS/poly(ethyleneimine) (PEI, branched), and PSS/poly(4-aminostyrene) (PAS), are prepd. and studied from a fundamental perspective in terms of multilayer compn. and crosslinking and also from an applied perspective through PEM membrane performance. The low mol. wt. cutoff (MWCO) of the PSS/PAH membranes signifies their dense structure (small mesh size), while ion retentions indicate that the dielec. exclusion mechanism is dominant. The PSS/PEI membranes are even denser and have higher selectivities. In contrast, the PSS/PAS membranes are more open, which is likely due to the lower charge d. of PAS compared to PEI and PAH. After chem. crosslinking, all of the PEM membranes are denser and therefore more selective and less permeable to water. Micropollutant retention increases for crosslinked PSS/PAH membranes, whereas little to no improvement is seen for crosslinked PSS/PAS and PSS/PEI membranes. Overall, this study shows that completely different membrane properties can be obtained by changing the type of polycation, thus demonstrating the high versatility of PEM-based membranes. In addn., for all PEM membranes, crosslinking acts as an addnl. tuning parameter that leads to denser and typically more selective layers.
- 27Kamp, J.; Emonds, S.; Wessling, M. Designing Tubular Composite Membranes of Polyelectrolyte Multilayer on Ceramic Supports with Nanofiltration and Reverse Osmosis Transport Properties. J. Membr. Sci. 2021, 620, 118851 DOI: 10.1016/J.MEMSCI.2020.11885127https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXisVGlurnM&md5=02c63843c046e2cef04903504aa5d3d6Designing tubular composite membranes of polyelectrolyte multilayer on ceramic supports with nanofiltration and reverse osmosis transport propertiesKamp, Johannes; Emonds, Stephan; Wessling, MatthiasJournal of Membrane Science (2021), 620 (), 118851CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Ceramic membranes are relevant for applications, which require mech. robustness and chem. stability. The prepn. of purely ceramic membranes for nanofiltration (NF) and reverse osmosis (RO) is a demanding process. Composite membranes comprise a mech. stable ceramic support and a functional polymeric sepn. layer, combining the advantages of both worlds. In this work, we present a mol. strategy to fabricate polyelectrolyte multi-layer membranes (PEMM) ranging from dense nanofiltration into the region of reverse osmosis deposited on tubular ceramic supports. A dynamic coating of PAH/PSS on a α-Al2O3 support membrane with pore sizes of 150 nm (MF) and 50 nm (UF) leads to a dense sepn. layer on the lumen side, with NaCl rejections above 90%. Coating solns. with increased ionic strength, as well as a subsequent covalent crosslinking of the amine groups of the PAH improve long term stability. The substitution of the polyanion PSS by PVSA, having a higher charge d., results in a remarkably low MWCO of 115 Da. This work indicates that balancing the charge d. of polymers with the ionic matrix can result in reverse osmosis type selective layers on ceramic support with pore size even as large as 150 nm.
- 28Stanton, B. W.; Harris, J. J.; Miller, M. D.; Bruening, M. L. Ultrathin, Multilayered Polyelectrolyte Films as Nanofiltration Membranes. Langmuir 2003, 19, 7038– 7042, DOI: 10.1021/LA034603A28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXltFKqur8%253D&md5=d257495bb65333a112677ec90bed0ff7Ultrathin, multilayered polyelectrolyte films as nanofiltration membranesStanton, Brian W.; Harris, Jeremy J.; Miller, Matthew D.; Bruening, Merlin L.Langmuir (2003), 19 (17), 7038-7042CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)This study shows that alternating polyelectrolyte deposition on porous supports can yield nanofiltration membranes that allow high water flux along with selective ion transport. Membranes composed of 4.5-5 layer pairs of poly(styrene sulfonate)/poly(allylamine hydrochloride) (PSS/PAH) on porous alumina allow water fluxes of 1-2 m3 m-2 day-1 at 4.8 bar while exhibiting MgSO4 rejections of 96%. Rejections of CaCl2 and Na2SO4 depend on polyelectrolyte deposition conditions and the compn. of the outer layer of the membrane. In general, divalent-ion rejection increases when the charge of the outer layer of the membrane has the same sign as the divalent ion being rejected. Increasing the concn. of the supporting electrolyte present during deposition of the terminating PSS layer of PSS/PAH membranes results in a higher surface charge, and hence higher Na2SO4 rejections (up to 95%). Nanofiltration with mixed solns. of NaCl and Na2SO4 yields Cl-/SO42- selectivities of about 30 when the top layer of PSS/PAH membranes is deposited from a soln. of high ionic strength. Capping PSS/PAH films with a layer of PAA increases Cl-/SO42- selectivities to values as high as 80. Interestingly, Cl-/SO42- selectivities in mixed solns. are higher than those detd. from single-salt measurements, presumably because diffusion potentials are different in the two cases. The high selectivities, water fluxes, and ion rejections of PSS/PAH membranes make them potentially attractive for applications in water and salt purifn.
- 29Jin, W.; Toutianoush, A.; Tieke, B. Use of Polyelectrolyte Layer-by-Layer Assemblies as Nanofiltration and Reverse Osmosis Membranes. Langmuir 2003, 19, 2550– 2553, DOI: 10.1021/LA020926F29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhslCmurs%253D&md5=b42ac6b5090d0f4c3fa8417fcc358f4eUse of Polyelectrolyte Layer-by-Layer Assemblies as Nanofiltration and Reverse Osmosis MembranesJin, Wanqin; Toutianoush, Ali; Tieke, BerndLangmuir (2003), 19 (7), 2550-2553CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Measurements of ion transport and water flux across ultrathin multilayered membranes of polyelectrolytes were carried out under nanofiltration and reverse osmosis conditions. The polyelectrolyte membranes were prepd. upon alternating electrostatic layer-by-layer adsorption of poly(vinylamine) (PVA) and poly(vinyl sulfate) (PVS) on porous supports. The pressure-driven transport of aq. electrolyte solns. contg. NaCl, Na2SO4, MgCl2, and MgSO4 in 1 and 10 mM concn. was investigated. For MgCl2 and MgSO4, a complete rejection was obsd. independently from the concn. of the feed soln. and the pressure applied. For NaCl and Na2SO4, the rejections were 84 and 96% at 5 bar, and 93.5 and 98.5% at 40 bar, resp. The hydraulic permeability of the composite membrane was 113.7 mL/(m2 h bar). It was only little affected by the presence of salt. At low and moderate pressure the membranes are suitable for water softening applications, while at pressures of 40 bar or higher they can be used for water desalination. Effects of the stirring of the feed soln. on the membrane characteristics are also discussed.
- 30Virga, E.; de Grooth, J.; Žvab, K. J.; de Vos, W. M. Stable Polyelectrolyte Multilayer-Based Hollow Fiber Nanofiltration Membranes for Produced Water Treatment. ACS Appl. Polym. Mater. 2019, 1, 2230– 2239, DOI: 10.1021/ACSAPM.9B0050330https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtlKlsbfO&md5=d55186abbe4c6790c2d03143ac0b99a4Stable Polyelectrolyte Multilayer-Based Hollow Fiber Nanofiltration Membranes for Produced Water TreatmentVirga, Ettore; de Grooth, Joris; Zvab, Klara; de Vos, Wiebe M.ACS Applied Polymer Materials (2019), 1 (8), 2230-2239CODEN: AAPMCD; ISSN:2637-6105. (American Chemical Society)Produced water (PW) constitutes a massive environmental issue due to its huge global prodn. as well as its complexity and toxicity. Membrane technol. could, however, convert this complex waste stream into an important source of water for reuse, but new and more efficient membranes are required. In particular, in the last few years, polyelectrolyte multilayers (PEMs) established themselves as a very powerful method to prep. hollow fiber-based nanofiltration (NF) membranes, and this membrane type and geometry would be ideal for PW treatment. Unfortunately, the presence of surfactants in PW can affect the stability of polyelectrolyte multilayers. In this work, we investigate the stability of polyelectrolyte multilayers toward different types of surfactant, initially on model surfaces. We find that chem. stable multilayers such as poly(diallyldimethylammonium chloride) (PDADMAC)/poly(sodium 4-styrenesulfonate) (PSS), based only on electrostatic interactions, are substantially desorbed by charged surfactants. For poly(allylamine hydrochloride) (PAH)/PSS multilayers, however, we demonstrate that chem. crosslinking by glutaraldehyde leads to surfactant stable layers. These stable PEM coatings can also be applied on hollow fiber support membranes to create hollow fiber NF membranes dedicated for PW treatment. Increased crosslinking time leads to more stable and more selective sepn. performance. These newly developed membranes were subsequently studied for the treatment of synthetic PW, consisting of freshly prepd. oil-in-water emulsions stabilized by hexade-cyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) in the presence of a mixt. of ions. For both types of produced water, the membranes show excellent oil removal (∼100%) and orgs. removal (TOC reduced up to ∼97%) as well as good divalent ion retentions (∼75% for Ca2+ and up to ∼80% for SO42-). Moreover, we observe a high flux recovery for both emulsions (100% for CTAB and 80% for SDS) and esp. for the CTAB emulsion a very low degree of fouling. These stable PEM-based hollow fiber membranes thus allow simultaneous deoiling and removal of small org. mols., particles, and divalent ions in a single step process while also demonstrating excellent membrane cleanability.
- 31Stratford, K.; Adhikari, R.; Pagonabarraga, I.; Desplat, J. C.; Cates, M. E. Colloidal Jamming at Interfaces: A Route to Fluid-Bicontinuous Gels. Science 2005, 309, 2198– 2201, DOI: 10.1126/SCIENCE.111658931https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVeksbnN&md5=bf8db2fa60b4c75759c761798e8600a1Colloidal Jamming at Interfaces: A Route to Fluid-Bicontinuous GelsStratford, K.; Adhikari, R.; Pagonabarraga, I.; Desplat, J.-C.; Cates, M. E.Science (Washington, DC, United States) (2005), 309 (5744), 2198-2201CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Colloidal particles or nanoparticles, with equal affinity for two fluids, are known to adsorb irreversibly to the fluid-fluid interface. We present large-scale computer simulations of the demixing of a binary solvent contg. such particles. The newly formed interface sequesters the colloidal particles; as the interface coarsens, the particles are forced into close contact by interfacial tension. Coarsening is markedly curtailed, and the jammed colloidal layer seemingly enters a glassy state, creating a multiply connected, solidlike film in three dimensions. The resulting gel contains percolating domains of both fluids, with possible uses as, for example, a microreaction medium.
- 32Herzig, E. M.; White, E. A.; Schofield, A. B.; Poon, W. C. K.; Clegg, P. S. Bicontinuous Emulsions Stabilized Solely by Colloidal Particles. Nat. Mater. 2007, 6, 966– 971, DOI: 10.1038/nmat205532https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlOmtL3L&md5=de2b813a1236db36597fc72f82873b55Bicontinuous emulsions stabilized solely by colloidal particlesHerzig, E. M.; White, K. A.; Schofield, A. B.; Poon, W. C. K.; Clegg, P. S.Nature Materials (2007), 6 (12), 966-971CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Recent large-scale computer simulations suggest that it may be possible to create a new class of soft solids, called bijels, by stabilizing and arresting the bicontinuous interface in a binary liq. demixing via spinodal decompn. using particles that are neutrally wetted by both liqs. The interfacial layer of particles is expected to be semi-permeable; hence, if realized, these new materials would have many potential applications, for example, as micro-reaction media. However, the creation of bijels in the lab. faces serious obstacles. In general, fast quench rates are necessary to bypass nucleation, so that only samples with limited thickness can be produced, which destroys the 3-dimensionality of the putative bicontinuous network. Also, even a small degree of unequal wettability of the particles by the 2 liqs. can lead to ill-characterized, lumpy interfacial layers and therefore irreproducible material properties. Here, the authors report a reproducible protocol for creating 3-dimensional samples of bijel in which the interfaces are stabilized by essentially a single layer of particles. To tune the mean interfacial sepn. in these bijels, and show that mech., they indeed behave as soft solids. These characteristics and their tunability will be of great value for microfluidic applications.
- 33Alvarez, N. J.; Walker, L. M.; Anna, S. L. A Non-Gradient Based Algorithm for the Determination of Surface Tension from a Pendant Drop: Application to Low Bond Number Drop Shapes. J. Colloid Interface Sci. 2009, 333, 557– 562, DOI: 10.1016/J.JCIS.2009.01.07433https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXktVCmsr0%253D&md5=f1e27556288a907784b74d7a7f5d0856A non-gradient based algorithm for the determination of surface tension from a pendant drop: Application to low Bond number drop shapesAlvarez, Nicolas J.; Walker, Lynn M.; Anna, Shelley L.Journal of Colloid and Interface Science (2009), 333 (2), 557-562CODEN: JCISA5; ISSN:0021-9797. (Elsevier B.V.)The pendant drop method is one of the most widely used techniques to measure the surface tension between gas-liq. and liq.-liq. interfaces. The method consists of fitting the Young-Laplace equation to the digitized shape of a drop suspended from the end of a capillary tube. The 1st use of digital computers to solve this problem used nonlinear least squares fitting and since then numerous subroutines and algorithms were reported for improving efficiency and accuracy. However, current algorithms which rely on gradient based methods have difficulty converging for almost spherical drop shapes (i.e. low Bond nos.). The authors present a nongradient based algorithm based on the Nelder-Mead simplex method to solve the least squares problem. The main advantage of using a nongradient based fitting routine is that it is robust against poor initial guesses and works for almost spherical bubble shapes. The authors have tested the algorithm against theor. and exptl. drop shapes to demonstrate both the efficiency and the accuracy of the fitting routine for a wide range of Bond nos. This algorithm allows for surface tension measurements corresponding to Bond nos. previously shown to be ill suited for pendant drop measurements.
- 34Khan, M. A.; Haase, M. F. Stabilizing Liquid Drops in Nonequilibrium Shapes by the Interfacial Crosslinking of Nanoparticles. Soft Matter 2021, 17, 2034– 2041, DOI: 10.1039/D0SM02120B34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXmsVKqsg%253D%253D&md5=855163573afc2ea8545ac8d9f201e190Stabilizing liquid drops in nonequilibrium shapes by the interfacial crosslinking of nanoparticlesKhan, Mohd A.; Haase, Martin F.Soft Matter (2021), 17 (8), 2034-2041CODEN: SMOABF; ISSN:1744-6848. (Royal Society of Chemistry)Droplets are spherical due to the principle of interfacial energy minimization. Here, we show that nonequil. droplet shapes can be stabilized via the interfacial self-assembly and crosslinking of nanoparticles. This principle allows for the stability of practically infinitely long liq. tubules and monodisperse cylindrical droplets. Droplets of oil-in-water are elongated via gravitational or hydrodynamic forces at a reduced interfacial tension. Silica nanoparticles self-assemble and crosslink on the interface triggered by the synergistic surface modification with hexyltrimethylammonium- and trivalent lanthanum-cations. The droplet length dependence is described by a scaling relationship and the rate of nanoparticle deposition on the droplets is estd. Our approach potentially enables the 3D-printing of Newtonian Fluids, broadening the array of material options for additive manufg. techniques.
- 35Kang, Z.; Yeung, A.; Foght, J. M.; Gray, M. R. Mechanical Properties of Hexadecane–Water Interfaces with Adsorbed Hydrophobic Bacteria. Colloids Surf., B 2008, 62, 273– 279, DOI: 10.1016/J.COLSURFB.2007.10.02135https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXisVWjt7o%253D&md5=e83af4b63db584ab259e50f90f6de77fMechanical properties of hexadecane-water interfaces with adsorbed hydrophobic bacteriaKang, Zhewen; Yeung, Anthony; Foght, Julia M.; Gray, Murray R.Colloids and Surfaces, B: Biointerfaces (2008), 62 (2), 273-279CODEN: CSBBEQ; ISSN:0927-7765. (Elsevier B.V.)This study focuses on how intact, hydrophobic bacteria in their stationary (i.e., non-dividing) phase could adsorb onto the hexadecane-water interface and alter its mech. properties. The two strains of bacteria used in forming the interfacial films were Acinetobacter venetianus RAG-1 and Rhodococcus erythropolis 20S-E1-c. Using the dynamic pendant drop technique, the film interfacial tension was monitored as the surface area was made to undergo transient changes. Under static conditions, both types of bacteria had no effect on the interfacial tension. When subjected to transient excitations, however, the two bacterial films exhibited clear and qual. similar rheol. properties: they responded as two-dimensional Maxwellian materials when the interfacial areas were dilated suddenly, but appeared to be purely elastic upon rapid area compression. Such rheol. behaviors are "non-linear" in that the responses of the tension to area dilation and contraction are not mirror images of one another. Despite their qual. similarities, the two types of film had very distinct film elasticities and relaxation times. The most striking difference between the two bacterial films was revealed under continuous redn. of area, when the A. venetianus RAG-1 system displayed a "paper-like" interface, whereas the interface of the R. erythropolis 20S-E1-c system was "soap film-like". These macroscopic observations could be explained by the surface ultrastructures of the two cell strains detd. using transmission electron microscopy.
- 36Binks, B. P.; Horozov, T. S. Colloidal Particles at Liquid Interfaces; Cambridge University Press, 2006; p 48.There is no corresponding record for this reference.
- 37Stocco, A.; Nobili, M. A Comparison between Liquid Drops and Solid Particles in Partial Wetting. Adv. Colloid Interface Sci. 2017, 247, 223– 233, DOI: 10.1016/J.CIS.2017.06.01437https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFyhs7fM&md5=8dd63784fdde2455724abd92195df48cA comparison between liquid drops and solid particles in partial wettingStocco, Antonio; Nobili, MaurizioAdvances in Colloid and Interface Science (2017), 247 (), 223-233CODEN: ACISB9; ISSN:0001-8686. (Elsevier B.V.)A review. In this crit. review we compare two geometries in partial wetting: a liq. drop on a planar substrate and a spherical particle at a planar liq. interface. We show that this comparison is far from being trivial even if the same phys. interactions are at play in both geometries. Similarities and differences in terms of free energies and frictions will be discussed. Contact angle hysteresis, the impact of surface roughness and line pinning on wetting will be described and compared to selected exptl. findings.
- 38Haase, M. F.; Brujic, J. Tailoring of High-Order Multiple Emulsions by the Liquid–Liquid Phase Separation of Ternary Mixtures. Angew. Chem., Int. Ed. 2014, 53, 11793– 11797, DOI: 10.1002/ANIE.20140604038https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsV2nurbK&md5=cb3fe2c47478f50144005a43f02baff3Tailoring of High-Order Multiple Emulsions by the Liquid-Liquid Phase Separation of Ternary MixturesHaase, Martin F.; Brujic, JasnaAngewandte Chemie, International Edition (2014), 53 (44), 11793-11797CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors show that phase sepn. in emulsions having "onion" topol. occurs through self-similar cycles of mass transfer, spinodal decompn. or nucleation, and coalescence into multiple layers. Mapping out the phase diagram shows a linear relationship between the diams. of concentric layers, the slope of which depends on the initial ternary compn. and the mol. wt. of the surfactant. These general rules quant. predict the no. of droplet layers (multiplicity), which we used to devise self-assembly routes for polymer capsules and liposomes. This technique is extended to the assembly of lipid-stabilized droplets with ordered internal structures.
- 39Aveyard, R.; Binks, B. P.; Clint, J. H. Emulsions Stabilised Solely by Colloidal Particles. Adv. Colloid Interface Sci. 2003, 100–102, 503– 546, DOI: 10.1016/S0001-8686(02)00069-639https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXisVGmurY%253D&md5=4fd8d564819399175201c36b575eab2fEmulsions stabilised solely by colloidal particlesAveyard, Robert; Binks, Bernard P.; Clint, John H.Advances in Colloid and Interface Science (2003), 100-102 (), 503-546CODEN: ACISB9; ISSN:0001-8686. (Elsevier Science B.V.)A review. The prepn. and properties of emulsions, stabilized solely by the adsorption of solid particles at the oil-H2O interface, are reviewed esp. in the light of our own work with particles of well-controlled surface properties. Where appropriate, comparison is made with the behavior of surfactant-stabilized emulsions. Hydrophilic particles tend to form oil-in-H2O (o/w) emulsions whereas hydrophobic particles form H2O-in-oil (w/o) emulsions. Many of the properties can be attributed to the very large free energy of adsorption for particles of intermediate wettability (contact angle at the oil-H2O interface, for example, between 50 and 130°). This effectively irreversible adsorption leads to extreme stability for certain emulsions and is in contrast to the behavior of surfactant mols. which are usually in rapid dynamic equil. between the oil-H2O interface and the bulk phases. There is evidence that, in some systems, weak flocculation of the particles improves the emulsion stability. Phase inversion from w/o to o/w can be brought about by increasing the vol. fraction of H2O. Emulsions close to this inversion point tend to be the most stable, again in contrast to surfactant systems. The vol. fraction needed for inversion depends on the particle wettability and the nature of the oil and these effects were rationalized in terms of surface energy components. Stable multiple emulsions (w/o/w and o/w/o) can be made using 2 types of particles with slightly different wettability. Similar multiple emulsions prepd. with 2 types of surfactant tend to be much less stable. The possibility of prepg. novel solid materials by evapg. solid-stabilized emulsions is also proposed. Finally the authors report on some extensions to the work of Levine et al. who obtained expressions for the free energy of formation of emulsion drops covered with close-packed monolayers of monodisperse spherical particles. In particular in the light of the observations that nanoparticles can act as excellent emulsion stabilizers, the authors have considered potential effects on the free energy of emulsion formation of the action of small (phys. realistic) pos. and neg. line tensions in the 3-phase contact lines skirting particles adsorbed at the droplet interfaces. The authors also explore the possibility that curvature properties of close-packed particle monolayers can affect emulsion properties in much the same way that surfactant monolayer properties influence emulsion type and stability.
- 40Binks, B. P.; Rodrigues, J. A.; Frith, W. J. Synergistic Interaction in Emulsions Stabilized by a Mixture of Silica Nanoparticles and Cationic Surfactant. Langmuir 2007, 23, 3626– 3636, DOI: 10.1021/LA063460040https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhvF2qsLs%253D&md5=f6b810af0a248e114e458f69bf1641bfSynergistic Interaction in Emulsions Stabilized by a Mixture of Silica Nanoparticles and Cationic SurfactantBinks, Bernard P.; Rodrigues, Jhonny A.; Frith, William J.Langmuir (2007), 23 (7), 3626-3636CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Using a range of complementary expts., a detailed study into the behavior of dodecane-water emulsions stabilized by a mixt. of silica nanoparticles and pure cationic surfactant was made. Both emulsifiers prefer to stabilize o/w emulsions. At high pH, particles are ineffective emulsifiers, whereas surfactant-stabilized emulsions become increasingly stable to coalescence with concn. In mixts., no emulsion phase inversion occurs although synergism between the emulsifiers leads to enhanced stability at either fixed surfactant concn. or fixed particle concn. Emulsions are most stable under conditions where particles have negligible charge and are most flocculated. Freeze fracture SEM confirms the presence of particle flocs at drop interfaces. At low pH, particles and surfactant are good emulsifiers alone. Synergism is also displayed in these mixts., with the extent of creaming being min. when particles are most flocculated. Expts. were undertaken to offer an explanation for the latter synergy. By detg. the adsorption isotherm of surfactant on particles in water, we show that surfactant addn. initially leads to particle flocculation followed by re-dispersion. Using suitable contact angle measurements at oil-water-solid interfaces, we show that silica surfaces initially become increasingly hydrophobic upon surfactant addn., and surfactant adsorption lowering the oil-water interfacial tension. A competition exists between the influence of surfactant on the contact angle and the tension in the attachment energy of a particle to the interface.
- 41Fuerstenau, D. W.; Jia, R. The Adsorption of Alkylpyridinium Chlorides and their Effect on the Interfacial Behavior of Quartz. Colloids Surf., A 2004, 250, 223– 231, DOI: 10.1016/J.COLSURFA.2004.04.09041https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVKlurjE&md5=ff8e8e13c90d30257fd05c09069b6244The adsorption of alkylpyridinium chlorides and their effect on the interfacial behavior of quartzFuerstenau, Douglas W.; Jia, RenheColloids and Surfaces, A: Physicochemical and Engineering Aspects (2004), 250 (1-3), 223-231CODEN: CPEAEH; ISSN:0927-7757. (Elsevier B.V.)This research was directed at understanding cationic surfactant adsorption phenomena on wet-ground natural quartz, mainly with dodecylpyridinium chloride as the model surfactant. How these surfactant ions adsorb at the interface was delineated through measurements of adsorption isotherms, zeta potentials, suspension stability, contact angles, induction times, and flotation response. Hydrocarbon chain assocn. of adsorbed surfactant ions (or self-assocn.) leads to 4 distinct adsorption regions as the concn. of surfactant is increased in soln. The same 4 regions manifest themselves in the behavior of all of the interfacial processes studied. At low concns., adsorption is controlled primarily by electrostatic interactions, but when the adsorbed surfactant ions begin to assoc. into hemimicelles at the surface, hydrophobic chain interactions control the adsorption process. The results of expts. with alkylpyridinium chlorides of 12, 14 and 16 C atoms can be normalized in terms of their CMCs, which clearly show that surface aggregation phenomena are driven by the same hydrophobic interactions that lead to micelle formation in bulk soln.
- 42Cui, Z. G.; Yang, L. L.; Cui, Y. Z.; Binks, B. P. Effects of Surfactant Structure on the Phase Inversion of Emulsions Stabilized by Mixtures of Silica Nanoparticles and Cationic Surfactant. Langmuir 2010, 26, 4717– 4724, DOI: 10.1021/LA903589E42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsV2nur3I&md5=f0db0d31a4f9a822022b484ba685d5f9Effects of Surfactant Structure on the Phase Inversion of Emulsions Stabilized by Mixtures of Silica Nanoparticles and Cationic SurfactantCui, Z.-G.; Yang, L.-L.; Cui, Y.-Z.; Binks, B. P.Langmuir (2010), 26 (7), 4717-4724CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Silica nanoparticles without any surface modification are not surface active at the toluene-water interface due to their extreme hydrophilicity but can be surface activated in situ by adsorbing cationic surfactant from water. This work studies the effects of the mol. structure of water-sol. cationic surfactant on the surface activation of the nanoparticles by emulsion characterization, adsorption and zeta potential measurements, dispersion stability expts., and detn. of relevant contact angles. An adsorbed cationic surfactant monolayer on particle surfaces is responsible for the wettability modification of the particles. In the presence of a trace amt. of cationic surfactant, the hydrophobicity of the particles increases, giving stable oil-in-water O/W(1) emulsions. At high surfactant concn. ( > cmc) the particle surface is retransformed to hydrophilic due to double-layer or hemimicelle formation, and the concn. of the free surfactant in the aq. phase is high enough to stabilize emulsions alone. O/W(2) emulsions, probably costabilized by free surfactant and particles, are then formed. The monolayer adsorption seems to be charge-site dependent. Thus, using single-chain trimethylammonium bromide surfactants or a double-head gemini cationic surfactant, the hydrophobicity of the particles achieved is not sufficient to stabilize water-in-oil (W/O) emulsions, and no phase inversion is induced. However, using a double-chain cationic surfactant, the chain d. on the particle surfaces endows them with a hydrophobicity high enough to stabilize W/O emulsions, and double phase inversion, O/W(1) → W/O → O/W(2), can then be achieved by increasing the surfactant concn.
- 43de Grooth, J.; Oborný, R.; Potreck, J.; Nijmeijer, K.; de Vos, W. M. The Role of Ionic Strength and Odd–Even Effects on the Properties of Polyelectrolyte Multilayer Nanofiltration Membranes. J. Membr. Sci. 2015, 475, 311– 319, DOI: 10.1016/J.MEMSCI.2014.10.04443https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVGhsr3M&md5=b7bb87e7dee4eb462fc16697a5650ff5The role of ionic strength and odd-even effects on the properties of polyelectrolyte multilayer nanofiltration membranesde Grooth, Joris; Oborny, Radek; Potreck, Jens; Nijmeijer, Kitty; de Vos, Wiebe M.Journal of Membrane Science (2015), 475 (), 311-319CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)The modification of membranes by polyelectrolytes via the Layer-by-Layer technique is an attractive method to obtain nanofiltration membranes. We prep. such membranes by alternatively coating a polycation (poly(diallyldimethylammonium chloride) (PDADAMAC)) and a polyanion (poly(styrene sulfonate) (PSS)) on a porous support. Depending on the coating conditions, hollow fiber membranes with rejections of up to 71% NaCl and 96% Na2SO4 are obtained. Moreover, we demonstrate that the final membrane properties can be easily controlled by variation of the ionic strength of the coating soln., the no. of layers and the choice of terminating polyelectrolyte layer. Coating at higher salt concns. results in thicker multilayers that are more open to permeation. Furthermore, we show that by taking the effect of the terminating layer (the so called "odd-even" effect) into account, information on the structure of the multilayers on the membrane is obtained. Depending on the coating conditions and no. of layers, two different regimes can be distinguished. Thinner layers show a pore-dominated regime, where the multilayer is coated on the inside of the pores. Thicker layers show a layer-dominated regime, in which case the multilayer is predominately coated on top of the pores. This conclusion is supported by our ion rejection measurements: for thin layers the rejections are primarily based on size exclusion, whereas for thick layers the ion rejections are based on Donnan exclusion.
- 44McAloney, R. A.; Sinyor, M.; Dudnik, V.; Cynthia Goh, M. Atomic Force Microscopy Studies of Salt Effects on Polyelectrolyte Multilayer Film Morphology. Langmuir 2001, 17, 6655– 6663, DOI: 10.1021/LA010136Q44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXms1Ont70%253D&md5=c3b5daf63884109f104ebe8fbb5ac7a9Atomic Force Microscopy Studies of Salt Effects on Polyelectrolyte Multilayer Film MorphologyMcAloney, Richard A.; Sinyor, Mark; Dudnik, Vyacheslav; Goh, M. CynthiaLangmuir (2001), 17 (21), 6655-6663CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The morphol. of multilayer films formed from poly(diallyldimethylammonium chloride) and poly(styrenesulfonic acid) deposited under a range of salt concns. (from 10-4 to 1.0 M) was investigated using at. force microscopy (AFM). Ten-bilayer films that were deposited with less than 0.3 M added NaCl were flat and featureless, with similar characteristics to the underlying silica substrate. When formed at and above this salt concn., a vermiculate morphol. was obsd. Thickness and roughness measurements were also carried out using the AFM and were found to increase with the concn. of added salt. The evolution of the vermiculate pattern was investigated by AFM studies of each layer that is deposited under high salt concn. (1.0 M NaCl). The first three bilayers were featureless and had a thickness of ∼6 nm/bilayer. A change in morphol. was obsd. by the fourth bilayer, and the av. thickness had increased to ∼46 nm/bilayer. These results may be explained in terms of a transition from an extended conformation to a more compact form that polyelectrolytes undergo as a function of the ionic strength of a soln.
- 45Goronja, J. M.; Janošević Ležaić, A. M.; Dimitrijević, B. M.; Malenović, A. M.; Stanisavljev, D. R.; Pejić, N. D. Determination of Critical Micelle Concentration of Cetyltrimethyl-Ammonium Bromide: Different Procedures for Analysis of Experimental Data. Chem. Ind. 2016, 70, 485– 492, DOI: 10.2298/HEMIND150622055GThere is no corresponding record for this reference.
- 46Miller, M. D.; Bruening, M. L. Correlation of the Swelling and Permeability of Polyelectrolyte Multilayer Films. Chem. Mater. 2005, 17, 5375– 5381, DOI: 10.1021/CM051222546https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVWhsLrO&md5=c7be8c8c98cc0f620cc806f7a151dfddCorrelation of the Swelling and Permeability of Polyelectrolyte Multilayer FilmsMiller, Matthew D.; Bruening, Merlin L.Chemistry of Materials (2005), 17 (21), 5375-5381CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)Alternating adsorption of polycations and polyanions on porous supports yields a variety of size-selective membranes whose swelling and transport properties depend on constituent polyelectrolytes, capping layer choice (polycation or polyanion), and deposition conditions. This report shows that in aq. expts., ellipsometrically detd. swelling percentages correlate well with nanofiltration (NF) rejections and diffusion dialysis fluxes. For example, hyaluronic acid (HA)/chitosan films swell 4 times more than poly(styrene sulfonate) (PSS)/poly(allylamine hydrochloride) coatings, and in NF expts., the HA/chitosan membranes permit a 250-fold greater fractional passage of sucrose. In general, films prepd. from polyelectrolytes with a high charge d. show low swelling and slow solute transport, presumably because of a high degree of ionic crosslinking. In the case of PSS/poly(diallyldimethylammonium chloride) (PDADMAC), PDADMAC-capped films can swell 4-fold more than their PSS-terminated counterparts, and as would be expected, glucose and sucrose transport rates in diffusion dialysis are about 1.7- and 17-fold more, resp., when these films end in PDADMAC. Polyelectrolyte multilayers also exhibit wide-ranging swelling properties in ethanol, but transport rates do not correlate with ethanol uptake. In this solvent, the d. of ionic cross-links and film hydrophobicity likely exert opposite effects on swelling, which could complicate the correlation between swelling and transport.
- 47Su, B.; Wang, T.; Wang, Z.; Gao, X.; Gao, C. Preparation and Performance of Dynamic Layer-by-Layer PDADMAC/PSS Nanofiltration Membrane. J. Membr. Sci. 2012, 423–424, 324– 331, DOI: 10.1016/J.MEMSCI.2012.08.04147https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFWit7bJ&md5=8e05da0d1c4d4551993e8d20ba51779cPreparation and performance of dynamic layer-by-layer PDADMAC/PSS nanofiltration membraneSu, Baowei; Wang, Tingting; Wang, Zongwen; Gao, Xueli; Gao, CongjieJournal of Membrane Science (2012), 423-424 (), 324-331CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Dynamic layer-by-layer (LBL) self-assembly technol. was used to prep. as few as three to five bilayers of poly(diallyl-dimethylammonium chloride) (PDADMAC) and poly(styrene sulfonate) (PSS) on neg. charged polysulfone (PS) ultrafiltration (UF) membranes of 50 kDa MWCO and compared with those of the static assembly membranes. The prepd. dynamic assembly (PDADMAC/PSS)4 nanofiltration (NF) membrane showed a permeation flux of 60 L m-2 h-1 at 1.0 MPa, much higher than that of the com. DL membrane (GE Osmonics, USA), but with a rejection of about 90% of SO42- which is relatively less than that of the DL membrane. The rejection performance showed that the dynamic-static assembly was more effective than others. Using dynamic-static assembly prepn., the rejection of (PDADMAC/PSS)3 membrane was about 90%, while the flux was about 55 L m-2 h-1 at 1.0 MPa. The surface morphol. of the prepd. LBL membranes were characterized by SEM and AFM, and no defect was found. The surface morphol. of the membrane prepd. by dynamic-static assembly was almost the same as the com. membranes. The anal. of filtration resistance indicated that the deposition of the first and second bilayer was crucial during the whole prepn. process.
- 48Notley, S. M.; Norgren, M. Adsorption of a Strong Polyelectrolyte to Model Lignin Surfaces. Biomacromolecules 2008, 9, 2081– 2086, DOI: 10.1021/BM800415U48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXns1elsbw%253D&md5=c063dac262d84bb440106b206ca29e1fAdsorption of a Strong Polyelectrolyte To Model Lignin SurfacesNotley, Shannon M.; Norgren, MagnusBiomacromolecules (2008), 9 (7), 2081-2086CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)The adsorption of a strong, highly charged cationic polyelectrolyte to a kraft lignin thin film was investigated as a function of the adsorbing soln. conditions using the quartz crystal microbalance. The polyelectrolyte, PDADMAC, with a mol. wt. of 100 kDa and one cationic charge group per monomer, was adsorbed to the anionically charged lignin film in the pH range 3.5-9.5 in electrolyte soln. of 0.1 to 100 mM NaCl. At low pH, the adsorbed amt. of PDADMAC was minimal, however, this increased as a function of increasing pH. Indeed, the surface excess increased significantly at about pH 8.5, where ionization of the phenolic groups on the lignin macromol. may be expected. Furthermore, at this elevated pH, the adsorbed amt. of PDADMAC decreased as the ionic strength of the soln. increased above 1 mM. This is due to the competitive adsorption of counterions to the lignin surface and indicates that the adsorption of PDADMAC to lignin is of a pure electrosorption nature.
- 49Bago Rodriguez, A. M.; Binks, B. P.; Sekine, T. Emulsions Stabilized with Polyelectrolyte Complexes Prepared from a Mixture of a Weak and a Strong Polyelectrolyte. Langmuir 2019, 35, 6693– 6707, DOI: 10.1021/ACS.LANGMUIR.9B0089749https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXovVyrtrs%253D&md5=214411b64a3df371c530bd357c6f1685Emulsions Stabilized with Polyelectrolyte Complexes Prepared from a Mixture of a Weak and a Strong PolyelectrolyteBago Rodriguez, Ana Maria; Binks, Bernard P.; Sekine, TomokoLangmuir (2019), 35 (20), 6693-6707CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The possibility of stabilizing emulsions with polyelectrolyte complexes (PEC) obtained from the interaction of two non-surface-active oppositely charged polyelectrolytes (PEL) is described. Poly(allylamine hydrochloride) (PAH) and poly(4-styrene sulfonate) sodium salt are selected as the weak cationic and the strong anionic polyelectrolyte, resp. Aq. polymer mixts. are investigated by light scattering to det. the size of the complexes and whether pptn. or complex coacervation occurs. The effects of PEL mixing ratio, pH, and PEL concn. are studied in detail. By increasing the pH, the transition ppt.-ppt./coacervate-coacervate-polymer soln. is obsd. At low pH, both PEL are fully ionized and therefore ppts. (soft particles) arise as a result of strong electrostatic interactions. By increasing the pH, the degree of ionization of PAH decreases and weak electrostatic interactions ensue, supporting the formation of coacervate droplets. The most stable oil-in-water emulsions are prepd. from aq. mixts. around charge neutralization. Although emulsions can be prepd. from coacervate droplet dispersions, their coalescence stability is worse than those stabilized by soft PEC particles. By increasing the PEL concn., the av. droplet diam. decreases and the fraction of cream in the emulsion increases for emulsions prepd. with PEC particles, following the limited coalescence model. However, at high concns., emulsion stability is slightly worse probably due to extensive aggregation of the particles. Viscous high internal phase emulsions can be prepd. at low pH in which oil droplets are deformed. Here, PEC particles are detected only at the oil-water interface. At lower oil content, excess particles form a network in the aq. phase aiding emulsion stability to coalescence.
- 50Dodoo, S.; Balzer, B. N.; Hugel, T.; Laschewsky, A.; Von Klitzing, R. Effect of Ionic Strength and Layer Number on Swelling of Polyelectrolyte Multilayers in Water Vapour. Soft Mater. 2013, 11, 157– 164, DOI: 10.1080/1539445X.2011.60720350https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltlGhsw%253D%253D&md5=2c02a74fc44a95b0d531ec48c5db205cEffect of ionic strength and layer number on swelling of polyelectrolyte multilayers in water vaporDodoo, Samuel; Balzer, Bizan N.; Hugel, Thorsten; Laschewsky, Andre; von Klitzing, RegineSoft Materials (2013), 11 (2), 157-164CODEN: SMOAAE; ISSN:1539-445X. (Taylor & Francis, Inc.)The swelling behavior of polyelectrolyte multilayers (PEMs) of poly(sodium-4 styrene sulfonate) (PSS) and poly(diallyl di-Me ammonium chloride) (PDADMAC) prepd. from aq. soln. of 0.1 M and 0.5 M NaCl are investigated by ellipsometry and AFM. From 1 double-layer up to 4 double-layers of 0.1 M NaCl, the amt. of swelling water in the PEMs decreases with increasing no. of adsorbed double layers due to an increase in polyelectrolyte d. as a result of the attraction between the pos. charged outermost PDADMAC layer and the Si substrate. From 6 double layers to 30 double layers, the attraction is reduced due to a much larger distance between substrate and outermost layer leading to a much lower polyelectrolyte d. and higher swelling water. In PEMs prepd. from aq. soln. of 0.5 M NaCl, the amt. of water constantly increases which is related to a monotonically decreasing polyelectrolyte d. with increasing no. of polyelectrolyte layers. Studies of the surface topol. also indicate a transition from a more substrate affected interphase behavior to a continuum properties of the polyelectrolyte multilayers. The threshold for the transition from interphase to continuum behavior depends on the prepn. conditions of the PEM.
- 51Guzmán, E.; Ritacco, H.; Rubio, J. E. F.; Rubio, R. G.; Ortega, F. Salt-Induced Changes in the Growth of Polyelectrolyte Layers of Poly(diallyl-dimethylammonium chloride) and Poly(4-styrene sulfonate of sodium. Soft Matter 2009, 5, 2130– 2142, DOI: 10.1039/B901193E51https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXls1yrsr4%253D&md5=9eee5d2319ea5afec56547e634aa3f0eSalt-induced changes in the growth of polyelectrolyte layers of poly(diallyl-dimethylammonium chloride) and poly(4-styrene sulfonate of sodium)Guzman, Eduardo; Ritacco, Hernan; Rubio, Jose E. F.; Rubio, Ramon G.; Ortega, FranciscoSoft Matter (2009), 5 (10), 2130-2142CODEN: SMOABF; ISSN:1744-683X. (Royal Society of Chemistry)Multilayers formed by the sodium salt of poly(4-styrene sulfonate), PSS, and poly(diallyldimethylammonium) chloride, PDADMAC, have been built by electrostatic self-assembly from polyelectrolyte aq. solns. of different ionic strengths. The growth of the multilayers has been followed using dissipative quartz crystal microbalance and ellipsometry. Neutron reflectometry and XPS data indicate that the PSS and PDADMAC layers interpenetrate leading to an almost homogeneous polymer film. The results show that on increasing [NaCl] the growing process changes from a linear to a non-linear regime. The comparison of the thickness values obtained from QCM and ellipsometry has allowed us to calc. the water content of the polymer film. The results agree with those obtained by neutron reflectometry. The anal. of the QCM data has provided values of the complex shear modulus, which are typical of a rubber-like polymer system. The anal. of the mass adsorbed calcd. by the ellipsometry measurements indicated that the charge compensation mechanism changes from intrinsic at low ionic strengths to mainly extrinsic at high ionic strengths. Finally, it was found that the response of a polymer film to a change in [NaCl] is rather different for films grown at low or at high ionic strengths.
- 52Chen, Y.; Kim, S.; Cohen, Y. Tuning the Hydraulic Permeability and Molecular Weight Cutoff (MWCO) of Surface Nano-Structured Ultrafiltration Membranes. J. Membr. Sci. 2021, 629, 119180 DOI: 10.1016/J.MEMSCI.2021.11918052https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXotVWqsLY%253D&md5=d340358d1dc9355ccc5b7d9b306c4838Tuning the hydraulic permeability and molecular weight cutoff (MWCO) of surface nano-structured ultrafiltration membranesChen, Yian; Kim, Soomin; Cohen, YoramJournal of Membrane Science (2021), 629 (), 119180CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Hydraulic permeability and mol. wt. cutoff (MWCO) performance tuning of polysulfone (PSf) ultrafiltration (UF) membrane was attained via surface modification with a tethered layer of poly(acrylic acid) (PAA). Surface nano-structured (SNS) PAA layer was synthesized onto base PSf UF membranes by atm. pressure plasma (APP) surface activation followed by graft polymn. (GP) of acrylic acid (AA). Through a systematic study, it was shown that effective SNS-PAA-PSf UF membrane performance tuning was feasible by adjustments of APP and graft polymn. conditions. It was shown, for the first time, that SNS-PAA-PSf membranes can be synthesized with a range of hydraulic permeability (spanning a factor of 1.1-2.6 in magnitude) for a given MWCO, or a range of MWCO (spanning a factor of 1.5-2.3 in magnitude) for a given hydraulic permeability, thereby overcoming the hydraulic permeability-MWCO tradeoff.
- 53Crittenden, J. C.; Trussell, R. R.; Hand, D. W.; Howe, K. J.; Tchobanoglous, G. MWH’s Water Treatment. In Principles and Design, 3rd ed.; John Wiley & Sons, 2012.There is no corresponding record for this reference.
- 54te Brinke, E.; Reurink, D. M.; Achterhuis, I.; de Grooth, J.; de Vos, W. M. Asymmetric Polyelectrolyte Multilayer Membranes with Ultrathin Separation Layers for Highly Efficient Micropollutant Removal. Appl. Mater. Today 2020, 18, 100471 DOI: 10.1016/J.APMT.2019.100471There is no corresponding record for this reference.
- 55Daerr, A.; Mogne, A. Pendent_Drop: An ImageJ Plugin to Measure the Surface Tension from an Image of a Pendent Drop. J. Open Res. Softw. 2016, 4, 3, DOI: 10.5334/JORS.97There is no corresponding record for this reference.
Supporting Information
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsami.2c10343.
Pendant drop shrinkage with nanoparticles (SI Video 1) (MP4)
Pendant drop shrinkage without nanoparticles (SI Video 2) (MP4)
Measurement of ternary phase diagrams; fiber precursor dispersion preparation; microfluidic device assembly; microfluidic fiber spinning; fluorescence emission spectra of Rhodamine 110 chloride and Nile red; transient solvent diffusion modeling; pendant drop experiments; droplet shape analysis; methanol as solvent for STrIPS; STrIPS fibers with Ludox nanoparticle dispersions at different pH; fiber internal surface area analysis; surface pore size distribution of STrIPS hollow fiber membrane; PSS/CTA+ complexation; polyelectrolyte functionalization of STrIPS hollow fibers; and STrIPS hollow fiber testing module; membrane separations with STrIPS hollow fibers (PDF)
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