Self-Patterning Polyelectrolyte Multilayer Films: Influence of Deposition Steps and Drying in a VacuumClick to copy article linkArticle link copied!
- Amir AzinfarAmir AzinfarInstitute of Physics, University of Greifswald, Felix-Hausdorff-Straße 6, D-17489 Greifswald, GermanyMore by Amir Azinfar
- Sven NeuberSven NeuberInstitute of Physics, University of Greifswald, Felix-Hausdorff-Straße 6, D-17489 Greifswald, GermanyMore by Sven Neuber
- Marie VancovaMarie VancovaInstitute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, 37005Ceske Budejovice, Czech RepublicFaculty of Science, University of South Bohemia, Branisovska 1760, 37005 Ceske Budejovice, Czech RepublicMore by Marie Vancova
- Jan SterbaJan SterbaFaculty of Science, University of South Bohemia, Branisovska 1760, 37005 Ceske Budejovice, Czech RepublicMore by Jan Sterba
- Vitezslav StranakVitezslav StranakFaculty of Science, University of South Bohemia, Branisovska 1760, 37005 Ceske Budejovice, Czech RepublicMore by Vitezslav Stranak
- Christiane A. Helm*Christiane A. Helm*Email: [email protected]. Phone: +49 3834 420 4710. Fax: +49 3834 420 4712.Institute of Physics, University of Greifswald, Felix-Hausdorff-Straße 6, D-17489 Greifswald, GermanyMore by Christiane A. Helm
Abstract
Typically, laterally patterned films are fabricated by lithographic techniques, external fields, or di-block copolymer self-assembly. We investigate the self-patterning of polyelectrolyte multilayers, poly(diallyldimethylammonium) (PDADMA)/poly(styrenesulfonate) (PSS)short. The low PSS molecular weight (Mw(PSSshort) = 10.7 kDa) is necessary because PSSshort is somewhat mobile within a PDADMA/PSSshort film, as demonstrated by the exponential growth regime at the beginning of the PDADMA/PSSshort multilayer build-up. No self-patterning was observed when the PDADMA/PSS film consisted of only immobile polyelectrolytes. Atomic force microscopy images show that self-patterning begins when the film consists of seven deposited PDADMA/PSSshort bilayers. When more bilayers are added, the surface ribbing evolved into bands, and circular domains were finally observed. The mean distance between the surface structures increased monotonously with the film thickness, from 70 to 250 nm. Scanning electron microscopy images showed that exposure to vacuum resulted in thinning of the film and an increase in the mean distance between domains. The effect is weaker for PSSshort-terminated films than for PDADMA-terminated films. The mechanism leading to domain formation during film build-up and the effect of post-preparation treatment are discussed.
This publication is licensed under
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
Non-Commercial (NC): Only non-commercial uses of the work are permitted.
No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
Non-Commercial (NC): Only non-commercial uses of the work are permitted.
No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
Non-Commercial (NC): Only non-commercial uses of the work are permitted.
No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
Non-Commercial (NC): Only non-commercial uses of the work are permitted.
No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
Non-Commercial (NC): Only non-commercial uses of the work are permitted.
No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
Introduction
Materials and Methods
Materials
Preparation of Multilayer Films
X-Ray Reflectometry
Ellipsometry
Atomic Force Microscopy (AFM)
Scanning Electron Microscopy (SEM)
Results and Discussion
Conclusions
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.langmuir.1c01409.
AFM images of the self-patterned and flat films measured in water (Figure S1); power spectral-density profiles obtained by the FFT analysis of the images shown in Figure 2 (Figure S2); X-ray reflectivity curves and deduced electron density profiles of different films (Figure S3); the film thickness and surface roughness in dependence of the number of deposited polycation/polyanion bilayers (Figure S4); vertical profiles of various films imaged by electron microscopy, both PSSshort- and PDADMA-terminated (Figures S5 and S6, respectively); and the diameter of the cross-sectional area of the domains (Figure S7) (PDF)
Terms & Conditions
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.
Acknowledgments
We are grateful for the financial support from the German Research Foundation (DFG) Collaborative Research Centre (CRC) ELAINE 1270 (SFB 1270/1 - 299150580) and support from the Czech Science Foundation Agency through the project GACR 19-20168S. Furthermore, we acknowledge the Laboratory of Electron Microscopy (LEM) of the Biology Centre of the Czech Academy of Sciences (CAS) supported by the Ministry of Education, Youth and Sports of the Czech Republic (LM2018129, Czech-BioImaging). Thanks to Dr. Heiko Ahrens, Dr. Peter Nestler, Dr. Heba Mohamad, Dr. Oliver Otto, Prof. Dr. Mihaela Delcea and Prof. Dr. Thomas Ihle for fruitful discussions.
References
This article references 50 other publications.
- 1Nestler, P.; Paßvogel, M.; Helm, C. A. Influence of polymer molecular weight on the parabolic and linear growth regime of PDADMAC/PSS multilayers. Macromolecules 2013, 46, 5622– 5629, DOI: 10.1021/ma400333fGoogle Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVKqtbbI&md5=378b1f60c6954d740e2f7d1d78257c0dInfluence of Polymer Molecular Weight on the Parabolic and Linear Growth Regime of PDADMAC/PSS MultilayersNestler, Peter; Passvogel, Malte; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2013), 46 (14), 5622-5629CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)The buildup of polyelectrolyte multilayers was investigated in soln. with multiple angle null-ellipsometry. Polyanion poly(styrene sulfonate) (PSS) and polycation poly(diallyldimethylammonium) (PDADMAC) were adsorbed sequentially from 0.1 M NaCl soln. First the films grew parabolically. After Ntrans deposited PDADMAC/PSS layer pairs a transition from a parabolic to a linear growth occurred. For mol. wts. above a threshold (Mw(PSS) > 25 kDa and Mw(PDADMAC) > 80 kDa), Ntrans is 15, the thickness per layer pair in the linear growth regime was 12.3 nm. If either the PDADMAC or the PSS mol. wt. decreased below the threshold value, Ntrans either fell (for PDADMAC, lowest value obsd. is 8) or rose (for PSS, highest value obsd. 33), resp. Simultaneously, in the linear growth regime, the thickness per layer pair decreases (down to 4.3 nm) or rises (up to 25 nm). Furthermore, for low mol. wt. PSS, three growth regimes were obsd.: exponential, parabolic, and linear. The opposite effect of PDADMAC and PSS mol. wt. redn. was discussed in terms of persistence lengths and linear charge d. The data suggest that mol. wt. provides a way to control growth and internal structure of polyelectrolyte multilayers.
- 2Hong, J. D.; Lowack, K.; Schmitt, J.; Decher, G. Layer-by-layer deposited multilayer assemblies of polyelectrolytes and proteins: from ultrathin films to protein arrays. Prog. Colloid Polym. Sci. 1993, 93, 98– 102, DOI: 10.1007/bfb0118482Google Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXmvVKqu7k%253D&md5=b85d77093ea1a17198ccc457c964f277Layer-by-layer deposited multilayer assemblies of polyelectrolytes and proteins: From ultrathin films to protein arraysHong, J. D.; Lowack, K.; Schmitt, J.; Decher, G.Progress in Colloid & Polymer Science (1993), 93 (TRENDS IN COLLOID AN), 98-102CODEN: PCPSD7; ISSN:0340-255X.We have recently introduced a new method of creating ultrathin films of polyelectrolytes based on the electrostatic attraction between opposite charges. Multilayer assemblies are adsorbed in a layer-by-layer fashion from aq. solns. of the polymers. The total film thickness can easily be adjusted by varying the ionic strength of the soln. Here, we report on the temp. stability and the water content of the multilayer assemblies. Furthermore, we have extended our concept to the incorporation of protein layers into films of synthetic polyelectrolytes. The well established system biotin/streptavidin was used to construct such multilayers, also by biospecific recognition. Adsorption of streptavidin onto previously photostructured precursor films leads to the deposition of the protein on selected areas on the substrate. The films were investigated by SAXS, Fourier Transform IR Spectroscopy (FTIR), and by fluorescence microscopy.
- 3Ghostine, R. A.; Markarian, M. Z.; Schlenoff, J. B. Asymmetric growth in polyelectrolyte multilayers. J. Am. Chem. Soc. 2013, 135, 7636– 7646, DOI: 10.1021/ja401318mGoogle Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnsFarsbY%253D&md5=c9d6707849cc2c16b1063e79d5ee5f7aAsymmetric Growth in Polyelectrolyte MultilayersGhostine, Ramy A.; Markarian, Marie Z.; Schlenoff, Joseph B.Journal of the American Chemical Society (2013), 135 (20), 7636-7646CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Radioactive counterions were used to track the ratio of pos. to neg. polymer repeat units within a polyelectrolyte multilayer made from poly(diallyldimethylammonium chloride), PDADMAC, and poly(styrene sulfonate), PSS. For this widely employed pair of "linearly" assembled polyelectrolytes it was found that the accepted model of charge overcompensation for each layer is incorrect. In fact, overcompensation at the surface occurs only on the addn. of the polycation, whereas PSS merely compensates the PDADMAC. After the assembly of about a dozen layers, excess pos. sites begin to accrue in the multilayer. Treating the surface as a reaction-diffusion region for pairing of polymer charges, a model profile was constructed. It is shown that different reaction-diffusion ranges of pos. and neg. polyelectrolyte charge lead to a blanket of glassy, stoichiometric complex growing on top of a layer of rubbery, PDADMAC-rich complex. Though overcompensation and growth was highly asym. with respect to the layer no., entirely conventional "linear" assembly of the multilayer was obsd. The impact of asym. growth on various properties of multilayers is discussed.
- 4Fu, J.; Schlenoff, J. B. Driving forces for oppositely charged polyion association in aqueous solutions: enthalpic, entropic, but not electrostatic. J. Am. Chem. Soc. 2016, 138, 980– 990, DOI: 10.1021/jacs.5b11878Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVKmsr8%253D&md5=874988141924788617f898cdebcddb6aDriving Forces for Oppositely Charged Polyion Association in Aqueous Solutions: Enthalpic, Entropic, but Not ElectrostaticFu, Jingcheng; Schlenoff, Joseph B.Journal of the American Chemical Society (2016), 138 (3), 980-990CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Driving forces for assocn. between oppositely charged biol. or synthetic polymers in aq. soln. have long been identified as electrostatic in origin. This attraction is broken down into an entropic component, due to loss of counterions, and an enthalpic component, stemming from Coulombic attraction between opposite charges. While the balance between entropic and enthalpic contributions shifts according to the conditions, the presence of exotherms or endotherms on mixing, though small, are viewed as signatures of Coulombic interactions which support theories of polyelectrolyte assocn. rooted in continuum electrostatics. Here, a head-to-head comparison is made between mechanisms based on electrostatics and those based on specific ion pairing, or ion exchange. Using a Hofmeister series of counterions for a common polycation, poly(diallyldimethylammonium), enthalpy changes on assocn. with poly(styrenesulfonate) are shown to derive from changes in water perturbation, revealed by Raman scattering studies of water O-H vibrations. The free energy for complexation is almost completely entropic over all salt concns.
- 5Costa, R. R.; Mano, J. F. Polyelectrolyte multilayered assemblies in biomedical technologies. Chem. Soc. Rev. 2014, 43, 3453– 3479, DOI: 10.1039/c3cs60393hGoogle Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmvFGmsb8%253D&md5=b962cc665bf249b8b207a913dfc2cab7Polyelectrolyte multilayered assemblies in biomedical technologiesCosta, Rui R.; Mano, Joao F.Chemical Society Reviews (2014), 43 (10), 3453-3479CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)Layer-by-layer (LbL) was first introduced as a surface modification technique based on the sequential spontaneous adsorption of at least two distinct materials onto planar substrates. In the last two decades, this technique has been expanded to the coating of more convoluted geometries with high levels of tailored functionalization or with structural purposes. In this review, the potential uses of LbL films in biomedical engineering based mainly on the assembly of polyelectrolytes are reviewed. Examples of recent developments are provided, from the modification of substrates to improve their biointegration or to add specialized properties, to the three-dimensional extrapolation of this technique to more complex structures for cell seeding, drug delivery devices, biosensors and customizable microreactors. Future strategies and opportunities are compared with current medical and laboratorial methodologies. Through them, it is expected that LbL will contribute greatly to the development of new functional devices with high perspectives of return for the administration of active agents, supports for cells in regenerative medicine and tissue engineering, biosensing and construction of microtissues and disease models in the lab.
- 6Richardson, J. J.; Björnmalm, M.; Caruso, F. Technology-driven layer-by-layer assembly of nanofilms. Science 2015, 348, aaa2491 DOI: 10.1126/science.aaa2491Google ScholarThere is no corresponding record for this reference.
- 7Picart, C.; Mutterer, J.; Richert, L.; Luo, Y.; Prestwich, G.; Schaaf, P.; Voegel, J.-C.; Lavalle, P. Molecular basis for the explanation of the exponential growth of polyelectrolyte multilayers. Proc. Natl. Acad. Sci., U.S.A. 2002, 99, 12531– 12535, DOI: 10.1073/pnas.202486099Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvFGiuro%253D&md5=ef85f688731df02b8970499ff36bb58aMolecular basis for the explanation of the exponential growth of polyelectrolyte multilayersPicart, C.; Mutterer, J.; Richert, L.; Luo, Y.; Prestwich, G. D.; Schaaf, P.; Voegel, J.-C.; Lavalle, P.Proceedings of the National Academy of Sciences of the United States of America (2002), 99 (20), 12531-12535CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The structure of poly(L-lysine) (PLL)/hyaluronan (HA) polyelectrolyte multilayers formed by electrostatic self-assembly is studied by using confocal laser scanning microscopy, quartz crystal microbalance, and optical waveguide lightmode spectroscopy. These films exhibit an exponential growth regime where the thickness increases exponentially with the no. of deposited layers, leading to micrometer thick films. Previously such a growth regime was suggested to result from an "in" and "out" diffusion of the PLL chains through the film during buildup, but direct evidence was lacking. The use of dye-conjugated polyelectrolytes now allows a direct three-dimensional visualization of the film construction by introducing fluorescent polyelectrolytes at different steps during the film buildup. We find that, as postulated, PLL diffuses throughout the film down into the substrate after each new PLL injection and out of the film after each PLL rinsing and further after each HA injection. As PLL reaches the outer layer of the film it interacts with the incoming HA, forming the new HA/PLL layer. The thickness of this new layer is thus proportional to the amt. of PLL that diffuses out of the film during the buildup step, which explains the exponential growth regime. HA layers are also visualized but no diffusion is obsd., leading to a stratified film structure. We believe that such a diffusion-based buildup mechanism explains most of the exponential-like growth processes of polyelectrolyte multilayers reported in the literature.
- 8Schönhoff, M. Layered polyelectrolyte complexes: physics of formation and molecular properties. J. Phys.: Condens. Matter 2003, 15, R1781– R1808, DOI: 10.1088/0953-8984/15/49/R01Google ScholarThere is no corresponding record for this reference.
- 9Gopinadhan, M.; Ivanova, O.; Ahrens, H.; Günther, J.-U.; Steitz, R.; Helm, C. A. The influence of secondary interactions during the formation of polyelectrolyte multilayers: Layer thickness, bound water and layer interpenetration. J. Phys. Chem. B 2007, 111, 8426– 8434, DOI: 10.1021/jp067402zGoogle Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXks1Sjurg%253D&md5=33d6e3b0e0a740446c1c5743663cbac4The Influence of Secondary Interactions during the Formation of Polyelectrolyte Multilayers: Layer Thickness, Bound Water and Layer InterpenetrationGopinadhan, Manesh; Ivanova, Oxana; Ahrens, Heiko; Guenther, Jens-Uwe; Steitz, Roland; Helm, Christiane A.Journal of Physical Chemistry B (2007), 111 (29), 8426-8434CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)X-ray and neutron reflectivity methods were used to study the structure and compn. of polyelectrolyte multilayers from poly(allyl amine) (PAH) and poly(styrene sulfonate) (PSS), as a function of prepn. conditions (salt concn. and soln. temp., T). The onset of a temp. effect occurs at 0.05 M NaCl (Debye length ∼ 1 nm). At 1 M salt, the film thickness increases by a factor of 3 on heating the deposition soln. from 5 to 60°. The PAH/PSS bilayer thickness is independent of the kind of salt (NaCl or KCl), yet its compn. is different (more bound water for NaCl). At low T, the internal roughness is 33% of the bilayer thickness; it increases to 60% at high T. The roughening is accompanied by a total loss of bound water. The temp. at which roughening starts is a function of the kind of salt (50° for NaCl and 35° for KCl). The strong temp. dependence and the eventual loss of bound water mols. may be attributed to hydrophobic force; however, there is an isotope effect, since the loss of bound water is less pronounced in deuterated (D2O) layers.
- 10Dubas, S. T.; Schlenoff, J. B. Swelling and smoothing of polyelectrolyte multilayers by salt. Langmuir 2001, 17, 7725– 7727, DOI: 10.1021/la0112099Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXotV2msbY%253D&md5=54309398463563275c46f3ec9cfa356bSwelling and Smoothing of Polyelectrolyte Multilayers by SaltDubas, Stephan T.; Schlenoff, Joseph B.Langmuir (2001), 17 (25), 7725-7727CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The swelling mechanism was studied of polyelectrolyte multilayers on exposure to aq. solns. contg. NaCl using in situ at. force microscopy. The polyelectrolyte combinations used are poly(styrene sulfonate) (PSS)/poly(acrylic acid) (PAA); PSS/poly(diallyldimethylammonium) (PDADMA); and PSS/poly(allylamine hydrochloride) (PAH). The quasilinear swelling response, used to est. swelling coeffs. and equil., exhibits orders of magnitude of difference, depending on the polyelectrolyte pair constituting the multilayer. The surface roughness of as-made multilayers decreased significantly upon annealing in NaCl solns.
- 11Ginger, D. S.; Zhang, H.; Mirkin, C. A. The evolution of dip-pen nanolithography. Angew. Chem., Int. Ed. 2004, 43, 30– 45, DOI: 10.1002/anie.200300608Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhsVelug%253D%253D&md5=17cccc48f10dd3193b5b42c25af90bbbThe evolution of dip-pen nanolithographyGinger, David S.; Zhang, Hua; Mirkin, Chad A.Angewandte Chemie, International Edition (2004), 43 (1), 30-35CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. The ability to tailor the chem. compn. and structure of a surface on the 1-100 nm length scale is important to researchers studying topics ranging from electronic conduction, to catalysis, to biol. recognition in nanoscale systems. Dip-pen nanolithog. (DPN) is a new scanning-probe based direct-write tool for generating such surface-patterned chem. functionality on the sub-100 nm length-scale, and it is a technique that is accessible to any researcher who can use an at. force microscope. This article introduces DPN and reviews the rapid growth of the field of DPN-related research over the past few years. Topics covered range from the development of new classes of DPN-compatible chem., to exptl. and theor. advances in the understanding of the processes controlling tip-substrate ink transport, to the implementation of micro-electromech. system (MEMS) based strategies for parallel DPN applications.
- 12Acikgoz, C.; Hempenius, M. A.; Huskens, J.; Vancso, G. J. Polymers in conventional and alternative lithography for the fabrication of nanostructures. Eur. Polym. J. 2011, 47, 2033– 2052, DOI: 10.1016/j.eurpolymj.2011.07.025Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlWltLfO&md5=818f1ee86ae35965448e6e1b8f5b3f11Polymers in conventional and alternative lithography for the fabrication of nanostructuresAcikgoz, Canet; Hempenius, Mark A.; Huskens, Jurriaan; Vancso, G. JuliusEuropean Polymer Journal (2011), 47 (11), 2033-2052CODEN: EUPJAG; ISSN:0014-3057. (Elsevier Ltd.)A review. This review provides a survey of lithog. techniques and the resist materials employed with these techniques. The first part focuses on the conventional lithog. methods used to fabricate complex micro- and nano-structured surfaces. In the second part, emphasis is placed on patterning with unconventional lithog. techniques such as printing, molding, and embossing, and on their development into viable, high-resoln. patterning technologies.
- 13Jackson, E. A.; Hillmyer, M. A. Nanoporous membranes derived from block copolymers: from drug delivery to water filtration. ACS Nano 2010, 4, 3548– 3553, DOI: 10.1021/nn1014006Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptFOrsLw%253D&md5=4a15249f94179c9f3759623a5ec803bfNanoporous Membranes Derived from Block Copolymers: From Drug Delivery to Water FiltrationJackson, Elizabeth A.; Hillmyer, Marc A.ACS Nano (2010), 4 (7), 3548-3553CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. With nanoscale pores, high porosity, narrow pore size distributions, and tunable chem. and mech. properties, block copolymers hold tremendous potential as robust, efficient, and highly selective sepn. membranes. Recent work by Yang et al. illustrates how block copolymers can be employed in the prepn. of membranes for use in controlled, long-term, protein-delivery devices. Their work demonstrates that highly efficient and tunable sepns. are possible with block copolymer membranes. Although significant progress over the past 10 years has advanced the quality, efficacy, and applicability of such membranes, more work is required before benefits are realized for other demanding applications such as water purifn.
- 14Mörke, C.; Rebl, H.; Finke, B.; Dubs, M.; Nestler, P.; Airoudj, A.; Roucoules, V.; Schnabelrauch, M.; Körtge, A.; Anselme, K.; Helm, C. A.; Nebe, J. B. Abrogated cell contact guidance on amino-functionalized microgrooves. ACS Appl. Mater. Interfaces 2017, 9, 10461– 10471, DOI: 10.1021/acsami.6b16430Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1czmsV2htw%253D%253D&md5=4154a91aacc0f3bd2cfe358230069edbAbrogated Cell Contact Guidance on Amino-Functionalized MicrogroovesMorke Caroline; Rebl Henrike; Nebe J Barbara; Finke Birgit; Dubs Manuela; Schnabelrauch Matthias; Nestler Peter; Helm Christiane A; Airoudj Aissam; Roucoules Vincent; Anselme Karine; Kortge AndreasACS applied materials & interfaces (2017), 9 (12), 10461-10471 ISSN:.Topographical and chemical features of biomaterial surfaces affect the cell physiology at the interface and are promising tools for the improvement of implants. The dominance of the surface topography on cell behavior is often accentuated. Striated surfaces induce an alignment of cells and their intracellular adhesion-mediated components. Recently, it could be demonstrated that a chemical modification via plasma polymerized allylamine was not only able to boost osteoblast cell adhesion and spreading but also override the cell alignment on stochastically machined titanium. In order to discern what kind of chemical surface modifications let the cell forget the underlying surface structure, we used an approach on geometric microgrooves produced by deep reactive ion etching (DRIE). In this study, we systematically investigated the surface modification by (i) methyl-, carboxyl-, and amino functionalization created via plasma polymerization processes, (ii) coating with the extracellular matrix protein collagen-I or immobilization of the integrin adhesion peptide sequence Arg-Gly-Asp (RGD), and (iii) treatment with an atmospheric pressure plasma jet operating with argon/oxygen gas (Ar/O2). Interestingly, only the amino functionalization, which presented positive charges at the surface, was able to chemically disguise the microgrooves and therefore to interrupt the microtopography induced contact guidance of the osteoblastic cells MG-63. However, the RGD peptide coating revealed enhanced cell spreading as well, with fine, actin-containing protrusions. The Ar/O2-functionalization demonstrated the best topography handling, e.g. cells closely attached even to features such as the sidewalls of the groove steps. In the end, the amino functionalization is unique in abrogating the cell contact guidance.
- 15Chen, L.; Yan, C.; Zheng, Z. Functional polymer surfaces for controlling cell behaviors. Mater. Today 2018, 21, 38– 59, DOI: 10.1016/j.mattod.2017.07.002Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1GgsbbJ&md5=c29afe2704b42a288474dbb02efd8c24Functional polymer surfaces for controlling cell behaviorsChen, Lina; Yan, Casey; Zheng, ZijianMaterials Today (Oxford, United Kingdom) (2018), 21 (1), 38-59CODEN: MTOUAN; ISSN:1369-7021. (Elsevier Ltd.)A review. Thorough understanding of how to control cell behaviors including cell adhesion, orientation, migration and differentiation on an artificial surface is crit. in materials and life sciences such as advanced biomedical engineering, tissue engineering, and cell-based bioassay. In nature, extracellular matrix (ECM) plays an important role in controlling cell behaviors. It can not only provide the cells with mech. support but also profoundly affect cell functions such as metab., movement and transport process. Functional polymer surface exhibits superior advantages over many other materials for use as artificial ECM owing to its excellent mech. properties, abundant chem. species and remarkable capability to form various topog. surfaces. In particular, surface chem., mech. properties and topog. of these functional polymers are found to be three major parameters for effective control of cell behaviors. This paper comprehensively reviews the fundamental understanding of functional polymer surfaces for controlling cell behaviors. Different fabrication methods to achieve functional polymer surfaces and the parameters for effective control of cell behaviors are discussed. The future prospects and challenges particularly in cell biomedical engineering are also discussed at the end of this review paper.
- 16Rodríguez-Hernández, J. Wrinkled interfaces: Taking advantage of surface instabilities to pattern polymer surfaces. Prog. Polym. Sci. 2015, 42, 1– 41, DOI: 10.1016/j.progpolymsci.2014.07.008Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlaht7rP&md5=9f3f32608cd666f3e1bde99caf95b1a5Wrinkled interfaces: Taking advantage of surface instabilities to pattern polymer surfacesRodriguez-Hernandez, JuanProgress in Polymer Science (2015), 42 (), 1-41CODEN: PRPSB8; ISSN:0079-6700. (Elsevier Ltd.)A review. The generation of nano-microstructured polymer film surfaces has been a challenge during the last decades. Advances in the fabrication of structured polymer surfaces to obtain micro and nano patterns have been accomplished following two different approaches, i.e., by adapting techniques, such as molding (embossing) or nano/microimprinting or by developing novel techniques including laser ablation, soft lithog. or laser scanning among others. Thus, higher resoln. capabilities are directly related with technol. advances. In contrast to the use of highly sophisticated tools required by the above mentioned techniques, surface instabilities produced by different mechanisms take advantage of the inherent properties of polymers to induce particular surface patterns. Some of the surface instabilities are well known since decades but novel and old known instability mechanisms have been only recently extended their use to pattern polymer surfaces. This recent interest relies on the rich and complex patterns obtained as a result of self-organizing processes that are rather difficult if not impossible to fabricate by using traditional patterning techniques. Among the approaches to obtain patterned interfaces by means of surface instabilities the formation of wrinkles is the most explored method and will be the center of this review. The fabrication approaches employed to induce wrinkle formation and the possibilities to fine tune the amplitude and period of the wrinkles, the functionality and their final morphol. are thoroughly described. Finally, an overview about the main applications in which buckled interfaces have been already employed or may have an impact in the near future is provided. Their use as templates, as flexible electronics, as supports with controlled wettability and/or adhesion or for biorelated applications are few of the fields in which the unique characteristics of wrinkled interfaces play distinguishing role.
- 17Bates, F. S. Polymer-polymer phase behavior. Science 1991, 251, 898– 905, DOI: 10.1126/science.251.4996.898Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXhsVCgsrk%253D&md5=53fc355f97cf74f3bf5e17e2c427509fPolymer-polymer phase behaviorBates, Frank S.Science (Washington, DC, United States) (1991), 251 (4996), 898-905CODEN: SCIEAS; ISSN:0036-8075.A review with 57 refs. on basic factors governing polymer-polymer phase behavior with emphasis on linear homopolymer blends and diblock copolymers as representative model mol. architectures. Equil. thermodn. and phase sepn. dynamics are reviewed and discussed.
- 18Halperin, A.; Tirrell, M.; Lodge, T. Tethered Chains in Polymer Microstructures. In Macromolecules: Synthesis, Order and Advanced Properties; Springer, 1992; pp 31– 71.Google ScholarThere is no corresponding record for this reference.
- 19Luo, M.; Epps, T. H., III Directed block copolymer thin film self-assembly: emerging trends in nanopattern fabrication. Macromolecules 2013, 46, 7567– 7579, DOI: 10.1021/ma401112yGoogle Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlKktLvK&md5=a526bee6f345280e88eae099081c6ad4Directed Block Copolymer Thin Film Self-Assembly: Emerging Trends in Nanopattern FabricationLuo, Ming; Epps, Thomas H., IIIMacromolecules (Washington, DC, United States) (2013), 46 (19), 7567-7579CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)A review. Block copolymers have garnered significant attention in the past few decades due to their ability to self-assemble into nanoscale structures (∼10-100 nm), making them ideal for emerging nanotechnologies, such as nanolithog., nanotemplating, nanoporous membranes, and ultrahigh-d. storage media. Many of these applications require thin film geometries, in which the block copolymers form well-ordered nanostructures and/or precisely controlled domain orientations. In this perspective, we discuss recent progress toward techniques that achieve directed self-assembly of block copolymer thin films. Substrate prepatterning, nanoimprint lithog., mol. transfer printing, solvent treatment, and zone processing approaches are highlighted. Finally, we comment on recent developments in high-throughput and in situ characterization methods, and we provide future research directions for thin film nanostructure refinement.
- 20Cini, N.; Tulun, T.; Decher, G.; Ball, V. Step-by-step assembly of self-patterning polyelectrolyte films violating (almost) all rules of layer-by-layer deposition. J. Am. Chem. Soc. 2010, 132, 8264– 8265, DOI: 10.1021/ja102611qGoogle Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvFaktbc%253D&md5=8c76ba8f7d4546c87992bec9d500e1e6Step-by-Step Assembly of Self-Patterning Polyelectrolyte Films Violating (Almost) All Rules of Layer-by-Layer DepositionCini, Nejla; Tulun, Tulay; Decher, Gero; Ball, VincentJournal of the American Chemical Society (2010), 132 (24), 8264-8265CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Because of its versatility, the layer-by-layer (LBL) assembly method has become a popular tool for prepg. multimaterial films, yet astonishingly little is known about the fundamental rules governing their deposition. Here we show an unusual case of self-patterning LBL films made from poly(allylamine hydrochloride) and poly(sodium phosphate). In such films, both the film thickness and the film roughness increase linearly with the no. of deposition steps up to a thickness of ∼60 nm. Even more surprising is the fact that the adsorption of individual "layers" of polyanions and polycations proceeds without a regular inversion of the ζ potential and with the occurrence of a growth instability at ∼75 layers. These findings underline the need to reconsider the fundamentals of polyelectrolyte multilayer film deposition.
- 21Chen, X.-c.; Ren, K.-f.; Chen, J.-y.; Wang, J.; Zhang, H.; Ji, J. Self-wrinkling polyelectrolyte multilayers: construction, smoothing and the underlying mechanism. Phys. Chem. Chem. Phys. 2016, 18, 31168– 31174, DOI: 10.1039/C6CP05419FGoogle Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslSntbfN&md5=61e6b5b30486aa929aaad873ac596973Self-wrinkling polyelectrolyte multilayers: construction, smoothing and the underlying mechanismChen, Xia-chao; Ren, Ke-feng; Chen, Jia-yan; Wang, Jing; Zhang, He; Ji, JianPhysical Chemistry Chemical Physics (2016), 18 (45), 31168-31174CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Introducing wrinkling or rough features into substrates is of great practical significance to construct various functional surfaces. Due to the sensitivity of assembled units towards environmental stimuli, the internals of layer-by-layer films can be readily adjusted to generate various micro- and nanostructures. We previously described a self-roughening polyelectrolyte multilayer (PEM) to facilitate the introduction of surface microstructures. In the present work, the growth process of PEI/PAA multilayer films was investigated and the mean size of the surface microstructures was found to increase linearly with the film thickness. The spontaneous formation of these surface features can be attributed to swelling-induced film deformation during the assembling process, which is similar to the surface wrinkling of hydrogels undergoing a vol. phase transition. When exposed to satd. humidity, the internal stress as well as the surface microstructures can be diminished spontaneously, leading to a flat surface over the substrates. Given the effect of the underlying film thickness on the characteristic wavelength of the surface wrinkles, multiscale surface microstructures can be readily realized by means of spatially presetting the distribution of the film thickness.
- 22Ghostine, R. A.; Jisr, R. M.; Lehaf, A.; Schlenoff, J. B. Roughness and salt annealing in a polyelectrolyte multilayer. Langmuir 2013, 29, 11742– 11750, DOI: 10.1021/la401632xGoogle Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlyjsrfI&md5=59dff5407c4e1dc0fef4bd463ffa65a5Roughness and Salt Annealing in a Polyelectrolyte MultilayerGhostine, Ramy A.; Jisr, Rana M.; Lehaf, Ali; Schlenoff, Joseph B.Langmuir (2013), 29 (37), 11742-11750CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The surface roughness of polyelectrolyte multilayers made from poly-(diallyldimethylammonium chloride), PDADMAC, and poly-(styrene sulfonate), PSS, was measured as a function of film deposition conditions. For dry multilayers, the significant roughness which builds up for thicker films is much more apparent for multilayers terminated with PSS. Corresponding roughness for PDADMA-capped multilayers may be seen by imaging in situ under electrolyte. Roughness may be substantially reduced, but not eliminated, by annealing in salt. Annealing does not lead to loss of polyelectrolyte from the film, even under conditions where the salt concn. is high enough to place the film properties beyond the glass transition. Roughness does not correlate with the mol. wt. of the polyelectrolyte and is thus not caused by soln. or film polymer chain conformations. The wavelength of the roughness features is approx. proportional to film thickness, which supports a mechanism whereby roughness is generated by anisotropic swelling due to water and polyelectrolyte addn. in a manner similar to water uptake in hydrogels. Roughness is preserved by the glassy PSS layer and probably incorporated within the film as it grows.
- 23Witt, M. A.; Valenga, F.; Blell, R.; Dotto, M. E.; Bechtold, I. H.; Felix, O.; Pires, A. T.; Decher, G. Layer-by-layer assembled films composed of “charge matched” and “length matched” polysaccharides: self-patterning and unexpected effects of the degree of polymerization. Biointerphases 2012, 7, 64, DOI: 10.1007/s13758-012-0064-4Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslajtbzN&md5=ea057df3288065c4184b8cf3fa71b059Layer-by-layer assembled films composed of "charge matched" and "length matched" polysaccharides: self-patterning and unexpected effects of the degree of polymerizationWitt, Maria A.; Valenga, Francine; Blell, Rebecca; Dotto, Marta E. R.; Bechtold, Ivan H.; Felix, Olivier; Pires, Alfredo T. N.; Decher, GeroBiointerphases (2012), 7 (1-4), 64CODEN: BJIOBN; ISSN:1559-4106. (Springer)The functionalization of chitosan with carboxymethyl groups allows zwitterionic or anionic chitosan derivs. to be obtained as a function of the degree of substitution. Here, we show that polyelectrolyte multilayers of chitosan and carboxymethylchitosan can be assembled by "dipping" or "spraying" to form strongly hydrated films in which both the polyanion and polycation possess the same polymer backbone ("matched chemistries"). Such films grow rapidly to fairly large thickness in very few assembly steps, esp. in the case of "matched" charge densities, and at. force microscopy reveals the formation of surface patterns that are dependent on the deposition conditions and on the no. of layers. Interestingly, the influence of the molar masses of the polyelectrolyte pairs on the complex formation is somewhat counterintuitive, the stronger complexation occurring between polyanions and polycations of different ("non-matching") lengths.
- 24Tanaka, T.; Sun, S.-T.; Hirokawa, Y.; Katayama, S.; Kucera, J.; Hirose, Y.; Amiya, T. Mechanical instability of gels at the phase transition. Nature 1987, 325, 796– 798, DOI: 10.1038/325796a0Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXhtl2jtLg%253D&md5=1d0a090aae700114cb8fd7d69d119ecaMechanical instability of gels at the phase transitionTanaka, Toyoichi; Sun, Shao Tang; Hirokawa, Yoshitsugu; Katayama, Seiji; Kucera, John; Hirose, Yoshiharu; Amiya, TakayukiNature (London, United Kingdom) (1987), 325 (6107), 796-8CODEN: NATUAS; ISSN:0028-0836.The pattern formation on acrylamide-Na acrylate copolymer [25085-02-3] gels during swelling was interpreted in terms of mech. instability caused by opposing forces on the upper and lower gel layers, one free to expand and the other to remain unswollen. Anal. predictions that the wavelength of the pattern was proportional to the gel thickness while the crit. osmotic pressure was independent of the gel thickness agreed with exptl. results.
- 25Rubinstein, M.; Semenov, A. N. Dynamics of entangled solutions of associating polymers. Macromolecules 2001, 34, 1058– 1068, DOI: 10.1021/ma0013049Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXislyhtg%253D%253D&md5=6005c7833708fe6c7c9bef83d7b50c83Dynamics of Entangled Solutions of Associating PolymersRubinstein, Michael; Semenov, Alexander N.Macromolecules (2001), 34 (4), 1058-1068CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)The process of making and breaking reversible bonds between assocg. groups (stickers) controls the dynamics of assocg. polymers. We develop a theory of "sticky reptation" to model the dynamics of entangled solns. of assocg. polymers with many stickers per chain. At a high degree of assocn., there are very few unassocd. stickers. It is therefore very difficult for a sticker to find a new partner to assoc. with after breaking the bond with an old one. Typically a sticker returns to its old partner following an unsuccessful search for a new one, prolonging the effective lifetime of reversible bonds. In the sticky reptation model, the search for a new partner is restricted to a part of the tube confining the entangled chain. Another important effect is the increase of the fraction of the interchain assocns. at the expense of the intrachain ones with increasing polymer concn. The sticky reptation model predicts a very strong concn. dependence of viscosity in good agreement with expts.
- 26Seo, J.; Lutkenhaus, J. L.; Kim, J.; Hammond, P. T.; Char, K. Effect of the layer-by-layer (LbL) deposition method on the surface morphology and wetting behavior of hydrophobically modified PEO and PAA LbL films. Langmuir 2008, 24, 7995– 8000, DOI: 10.1021/la800906xGoogle Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXntlaru7Y%253D&md5=7d09fbc4cf2abc2f6f33771bf33cc8d2Effect of the Layer-by-Layer (LbL) Deposition Method on the Surface Morphology and Wetting Behavior of Hydrophobically Modified PEO and PAA LbL FilmsSeo, Jinhwa; Lutkenhaus, Jodie L.; Kim, Junoh; Hammond, Paula T.; Char, KookheonLangmuir (2008), 24 (15), 7995-8000CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)We demonstrate that the surface morphol. and surface-wetting behavior of layer-by-layer (LbL) films can be controlled using different deposition methods. Multilayer films based upon hydrogen-bonding interactions between hydrophobically modified poly(ethylene oxide) (HM-PEO) and poly(acrylic acid) (PAA) have been prepd. using the dip- and spin-assisted LbL methods. A three-dimensional surface structure in the dip-assisted multilayer films appeared above a crit. no. of layer pairs owing to the formation of micelles of HM-PEO in its aq. dipping soln. In the case of spin-assisted HM-PEO/PAA multilayer films, no such surface morphol. development was obsd., regardless of the layer pair no., owing to the limited rearrangement and aggregation of HM-PEO micelles during spin deposition. The contrasting surface morphologies of the dip- and spin-assisted LbL films have a remarkable effect on the wetting behavior of water droplets. The water contact angle of the dip-assisted HM-PEO/PAA LbL films reaches a max. at an intermediate layer pair no., coinciding with the crit. no. of layer pairs for surface morphol. development, and then decreases rapidly as the surface structure is evolved and amplified. In contrast, spin-assisted HM-PEO/PAA LbL films yield a nearly const. water contact angle due to the surface chem. compn. and roughness that is uniform independent of layer pair no. We also demonstrate that the multilayer samples prepd. using both the dip- and spin-assisted LbL methods were easily peeled away from any type of substrate to yield free-standing films; spin-assisted LbL films appeared transparent, while dip-assisted LbL films were translucent.
- 27Sill, A.; Nestler, P.; Weltmeyer, A.; Paßvogel, M.; Neuber, S.; Helm, C. A. Polyelectrolyte Multilayer Films from Mixtures of Polyanions: Different Compositions in Films and Deposition Solutions. Macromolecules 2020, 53, 7107– 7118, DOI: 10.1021/acs.macromol.0c01089Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsFehtLfK&md5=a5035c6a59bd5d1ab34ed5433880c69bPolyelectrolyte Multilayer Films from Mixtures of Polyanions: Different Compositions in Films and Deposition SolutionsSill, Annekatrin; Nestler, Peter; Weltmeyer, Antonia; Passvogel, Malte; Neuber, Sven; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2020), 53 (16), 7107-7118CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Polyelectrolyte multilayers are usually prepd. from polydisperse polyelectrolytes. It is desirable to measure and control multilayer compn. when it deviates from the deposition soln. With neutron reflectivity, multilayers prepd. from PDADMA and binary mixts. of long deuterated PSSdlong (80.8 kDa) and short protonated PSSshort (10.6 kDa) were investigated. A small amt. of PSSlong in the deposition soln. led to a disproportionate increase of PSSlong in the film, and completely suppressed the exponential growth regime. Adsorption kinetics were studied with in situ ellipsometry: (i) During adsorption of a PSS layer, the PSSlong fraction increased with adsorption time; PSSshort could desorb, while PSSlong adsorbed irreversibly. (ii) During adsorption of a PDADMA layer, a fast thickness increase was followed by a slow thickness decrease. This was attributed to the formation of PDADMA/PSSshort complexes, which eventually desorbed. The desorbed thickness depended on the no. of layers deposited. The mechanism of layer formation is attributed to the asym. growth of PDADMA/PSS multilayers, as supported by the adsorption kinetics of multilayers prepd. from one kind of PSS.
- 28Akkaoui, K.; Yang, M.; Digby, Z. A.; Schlenoff, J. B. Ultraviscosity in entangled polyelectrolyte complexes and coacervates. Macromolecules 2020, 53, 4234– 4246, DOI: 10.1021/acs.macromol.0c00133Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXpt1KqsrY%253D&md5=bbba259587a28e0d2de024ae3181840aUltraviscosity in Entangled Polyelectrolyte Complexes and CoacervatesAkkaoui, Khalil; Yang, Mo; Digby, Zachary A.; Schlenoff, Joseph B.Macromolecules (Washington, DC, United States) (2020), 53 (11), 4234-4246CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)The spontaneous assocn. of oppositely charged polyelectrolytes is an example of liq.-liq. phase sepn. The resulting hydrated polyelectrolyte complexes or coacervates, both termed "PECs", display a wide range of viscosities. In addn. to the usual dependence of viscosity on mol. wt. and vol. fraction expected for condensed neutral polymers, PECs also contain dense charge pairing between pos., Pol+, and neg., Pol-, repeat units. These "stickers" slow polymer chain dynamics on multiple length scales. Pol+Pol- charge pairs may be broken by the addn. of salt to solns. contacting PECs, reducing viscosity ("saloplasticity"). Here, the dynamics of matched pairs of a polycation, poly(methacryloylaminopropyltrimethylammonium chloride), and polyanion, sodium poly(methacrylate), with mol. wts. considerably above the entanglement concn., were measured as a function of temp. and salt concn. The dynamics of NaCl ions in PECs were also detd. and correlated to the segmental relaxation times, which control viscosity. A suite of relaxation times corresponding to ion, monomer, Pol+Pol- pair exchange, entanglement, and reptation was detd. or estd. The zero-shear viscosity, η0, was found to be an unusually strong function of mol. wt., with the scaling η0 ≈ M5. A polymer coil size, measured by small-angle neutron scattering, was used in concert with new quant. expressions to provide a good fit of theory to expt. for this unusual scaling.
- 29Sill, A.; Nestler, P.; Azinfar, A.; Helm, C. A. Tailorable Polyanion Diffusion Coefficient in LbL Films: The Role of Polycation Molecular Weight and Polymer Conformation. Macromolecules 2019, 52, 9045– 9052, DOI: 10.1021/acs.macromol.9b01761Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitFCit7rK&md5=a9227e4d9c456819a9c3ef93c003aba1Tailorable Polyanion Diffusion Coefficient in LbL Films: The Role of Polycation Molecular Weight and Polymer ConformationSill, Annekatrin; Nestler, Peter; Azinfar, Amir; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2019), 52 (22), 9045-9052CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Assembly of oppositely charged macromols. (proteins, DNA, polyelectrolytes) is often used for surface modification and functionalization. Yet, it remains a challenge to control the position and mobility of the mols. within the assembly. Using polyelectrolyte multilayers as model systems, we study the diffusion const. of the polyanion PSS. DPSS could be varied by 5 orders of magnitude. Two parameters were found to be important: (i) the conformation of the polyelectrolytes and (ii) the mol. wt. of the polycation (Mw(PDADMA)); the latter was the dominant parameter. Independent of conformation, by increasing Mw(PDADMA), DPSS decreased by at least 3 orders of magnitude when Mw(PDADMA) increased by a factor of seven. The decrease was stronger than predicted by any scaling law; it was either exponential or abrupt after DPSS was almost const. for low Mw(PDADMA). The polymer conformation was adjusted with the salt concn. in the prepn. soln. Flatter and less entangled chains led to an increase in DPSS. These findings on the time dependence of the internal structure of assemblies are discussed in the context of network theory.
- 30Hoogeveen, N.; Stuart, M. C.; Fleer, G.; Böhmer, M. Formation and stability of multilayers of polyelectrolytes. Langmuir 1996, 12, 3675– 3681, DOI: 10.1021/la951574yGoogle Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XjvFWksLw%253D&md5=03926b7941609ba1f1c3e8fab5cc3e5dFormation and Stability of Multilayers of PolyelectrolytesHoogeveen, Nynke G.; Cohen Stuart, Martien A.; Fleer, Gerard J.; Boehmer, Marcel R.Langmuir (1996), 12 (15), 3675-3681CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Sequential addn. of anionic and cationic polyelectrolytes may lead to the formation of multilayers at a solid surface. The buildup of such multilayers is characterized by a stepwise increase of the adsorbed amt. and layer thickness and by alternating highly pos. and highly neg. values for the ζ-potential. The prime variables which det. the stability of these structures are the polymer charge and the ionic strength. Very stable multilayers are formed when both polymers are highly charged and when the ionic strength is low. For weakly stable multilayers complexation at the surface may first occur, followed by desorption of the complexes. For strongly charged polyelectrolytes the charge stoichiometry, which is not always 1:1, seems to be unique for each pair of polyelectrolytes; no influence of the substrate, of the pH, or of the ionic strength could be obsd.
- 31Dodoo, S.; Steitz, R.; Laschewsky, A.; von Klitzing, R. Effect of ionic strength and type of ions on the structure of water swollen polyelectrolyte multilayers. Phys. Chem. Chem. Phys. 2011, 13, 10318– 10325, DOI: 10.1039/c0cp01357aGoogle Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmtFyksr4%253D&md5=57421a26406ee81e86f97d03862df01aEffect of ionic strength and type of ions on the structure of water swollen polyelectrolyte multilayersDodoo, S.; Steitz, R.; Laschewsky, A.; von Klitzing, R.Physical Chemistry Chemical Physics (2011), 13 (21), 10318-10325CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)This study addresses the effect of ionic strength and type of ions on the structure and water content of polyelectrolyte multilayers. Polyelectrolyte multilayers of poly(sodium-4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC) prepd. at different NaF, NaCl and NaBr concns. have been investigated by neutron reflectometry against vacuum, H2O and D2O. Both thickness and water content of the multilayers increase with increasing ionic strength and increasing ion size. Two types of water were identified, "void water" which fills the voids of the multilayers and does not contribute to swelling but to a change in scattering length d. and "swelling water" which directly contributes to swelling of the multilayers. The amt. of void water decreases with increasing salt concn. and anion radius while the amt. of swelling water increases with salt concn. and anion radius. This is interpreted as a denser structure in the dry state and larger ability to swell in water (sponge) for multilayers prepd. from high ionic strengths and/or salt soln. of large anions. No exchange of hydration water or replacement of H by D was detected even after eight hours incubation time in water of opposing isotopic compn.
- 32Zerball, M.; Laschewsky, A.; von Klitzing, R. Swelling of polyelectrolyte multilayers: The relation between, surface and bulk characteristics. J. Phys. Chem. B 2015, 119, 11879– 11886, DOI: 10.1021/acs.jpcb.5b04350Google Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlWmtbrF&md5=99c4ec5ba4baf38a70b0805933bd9b17Swelling of Polyelectrolyte Multilayers: The Relation Between, Surface and Bulk CharacteristicsZerball, Maximilian; Laschewsky, Andre; von Klitzing, RegineJournal of Physical Chemistry B (2015), 119 (35), 11879-11886CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)The odd-even effect, i.e., the influence of the outermost layer of polyelectrolyte multilayers (PEMs) on their swelling behavior, is investigated. For that purpose poly(styrene sodium sulfonate) (PSS)/poly(diallyl-dimethylammonium chloride) (PDADMAC) polyelectrolyte multilayers are studied in air with 1% relative humidity (RH), 30% RH, 95% RH, and in liq. water by ellipsometry, at. force microscopy (AFM), and X-ray reflectometry (XRR). Since the total amt. of water uptake in swollen PEMs is divided into two fractions, the void water and the swelling water, a correct evaluation of the odd-even effect is only possible if both fractions are examd. sep. In order to allow measuring samples over a larger thickness regime the investigation of a larger amt. of samples is required. Therefore, the concept of sepg. void water from swelling water using neutron reflectometry is for the first time transferred to ellipsometry. The subsequent anal. of swelling water, void water, and roughness revealed the existence of two types of odd-even effects: an odd-even effect which addresses only the surface of the PEM (surface-odd-even effect) and an odd-even effect which addresses also the bulk of the PEM (bulk-odd-even effect). The appearance of both effects is dependent on the environment; the surface-odd-even effect is only detectable in humid air while the bulk-odd-even effect is only detectable in liq. water. The bulk-odd-even effect is related to the osmotic pressure between the PEM and the surrounding water. A correlation between the amt. of void water and both odd-even effects is not found. The amt. of void water is independent of the terminated layer and the thickness of PEMs.
- 33de 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 Scholar33https://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.
- 34Han, L.; Mao, Z.; Wu, J.; Zhang, Y.; Gao, C. Influences of surface chemistry and swelling of salt-treated polyelectrolyte multilayers on migration of smooth muscle cells. J. R. Soc., Interface 2012, 9, 3455– 3468, DOI: 10.1098/rsif.2012.0546Google Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhvValu73F&md5=7d06f8cdf339acc95f7d55537fa53fc6Influences of surface chemistry and swelling of salt-treated polyelectrolyte multilayers on migration of smooth muscle cellsHan, Lulu; Mao, Zhengwei; Wu, Jindan; Zhang, Yuying; Gao, ChangyouJournal of the Royal Society, Interface (2012), 9 (77), 3455-3468CODEN: JRSICU; ISSN:1742-5689. (Royal Society)The cell migration plays a crucial role in a variety of physiol. and pathol. processes and can be regulated by the cell-substrate interactions. We found previously that the poly (sodium 4-styrenesulfonate) (PSS)/poly(diallyldimethylammonium) chloride (PDADMAC) multilayers post-treated in 1-5 M NaCl solns. result in continuous changes of their physicochem. properties such as thickness, chem. compn., surface charge, swelling ratio and wettability. In this study, the responses of human smooth muscle cells (SMCs) on these salt-treated multilayers, particularly the governing factors of cellular migration that offer principles for designing therapeutics and implants, were disclosed. The cell migration rate was slowest on the 3 M NaCl-treated multilayers, which was comparable with that on tissue culture plates, but it was highest on 5 M NaCl-treated multilayers. To elucidate the intrinsic mechanisms, cell adhesion, proliferation, adhesion and related gene expressions were further investigated. The SMCs preferred to attach, spread and proliferate on the PSS-dominated surfaces with well-organized focal adhesion and act in fibers, esp. on the 3 M NaCl-treated multilayers, while were kept round and showed low viability on the PDADMAC-dominated surfaces. The relative mRNA expression levels of adhesion-related genes such as fibronectin, laminin and focal adhesion kinase, and migration-related genes such as myosin IIA and Cdc42 were compared to explain the different cellular behaviors. These results reveal that the surface chem. and the swelling of the salt-treated multilayers govern the cell migration behaviors.
- 35Kim, B. J.; Choi, I. S.; Yang, S. H. Cytocompatible Coating of Yeast Cells with Antimicrobial Chitosan through Layer-by-Layer Assembly. Bull. Korean Chem. Soc. 2016, 37, 1850– 1853, DOI: 10.1002/bkcs.10963Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1ejtrjF&md5=5449090b35cada3e86abb1a3afbef0c0Cytocompatible Coating of Yeast Cells with Antimicrobial Chitosan through Layer-by-Layer AssemblyKim, Beom Jin; Choi, Insung S.; Yang, Sung HoBulletin of the Korean Chemical Society (2016), 37 (11), 1850-1853CODEN: BKCSDE; ISSN:0253-2964. (Wiley-VCH Verlag GmbH & Co. KGaA)Cytocompatible Coating of Yeast Cells with Antimicrobial Chitosan through Layer-by-Layer Assembly.
- 36Mohamad, H. S.; Neuber, S.; Helm, C. A. Surface Forces of Asymmetrically Grown Polyelectrolyte Multilayers: Searching for the Charges. Langmuir 2019, 35, 15491– 15499, DOI: 10.1021/acs.langmuir.9b01787Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhslWgs7zN&md5=08b98683f60000d3c9eb25f88d77603cSurface Forces of Asymmetrically Grown Polyelectrolyte Multilayers: Searching for the ChargesMohamad, Heba S.; Neuber, Sven; Helm, Christiane A.Langmuir (2019), 35 (48), 15491-15499CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The surface forces of polyelectrolyte multilayer films are measured. Films are made from polyelectrolytes with different linear charge d., poly(diallyldiemethylammonium) (PDADMA) and poly(styrenesulfonate) (PSS). Films were prepd. at 0.1 M NaCl, and at this ionic strength the multilayer surfaces are flat, uncharged and partially hydrophobic. For PSS-terminated films on decrease of the ionic strength electrostatic forces are found. At the beginning of multilayer formation, in the parabolic growth regime, the surface charge d. is neg. When the multilayer thickness increases linearly with the no. of deposited layers, the surface charge d. is pos. and low (one charge per 200-400 nm2). This reversal of surface charge is due to excess PDADMA-monomers within the film, as expected from asym. multilayers. On diln., PDADMA terminated films show steric forces, chains protrude into the soln. and form a pseudobrush. The brush scales as a polyelectrolyte brush. The thickness of the pseudobrush is independent of the no. of deposited layers, with a low grafting d. (1900 nm2 per chain). We suggest a model of polyelectrolyte multilayer formation: PDADMA with its low linear charge d. adsorbs with loosely bound chains. Monovalent anions within the film provide an elec. neutral surface. When PSS adsorbs onto a PDADMA-terminated multilayer, PSS replaces monovalent anions and forms electrostatic monomer-monomer bonds. The bond formation occurs within the polyelectrolyte multilayer; no surface charge is found.
- 37Paßvogel, M.; Nestler, P.; Köhler, R.; Soltwedel, O.; Helm, C. A. Influence of Binary Polymer Mixtures on the Nonlinear Growth Regimes of Polyelectrolyte Multilayer Films. Macromolecules 2016, 49, 935– 949, DOI: 10.1021/acs.macromol.5b01674Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVGms78%253D&md5=6b9da38e05eea8e36253e60ff9985bc4Influence of Binary Polymer Mixtures on the Nonlinear Growth Regimes of Polyelectrolyte Multilayer FilmsPassvogel, Malte; Nestler, Peter; Koehler, Ralf; Soltwedel, Olaf; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2016), 49 (3), 935-949CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)We report on ellipsometric studies of the nonlinear growth regimes of electrostatically assembled polyelectrolyte multilayer films under in situ conditions. Poly(styrenesulfonate) (PSS) and poly(diallylmethylammonium) (PDADMA) with different mol. wts. in 0.1 mol/L NaCl are used. Always, the linear growth is preceded by a parabolic growth regime. For films made from binary PDADMA mixts., the compns. in the film and the adsorption soln. are nearly identical. To explain these findings, a mol. model that describes the parabolic growth quant. is introduced. Neutron reflectivity of films prepd. from PSS mol. wt. above a threshold, >25 kDa, shows that its center of mass is vertically immobile, in both the parabolic and linear growth regimes. Below 25 kDa, the multilayer buildup starts with an exponential growth regime, and pronounced PSS interdiffusion is found with neutron reflectivity. The exponential buildup regime is extended on decrease of PSS mol. wt. For films made from binary PSS mixts., addn. of less than 1 mol % PSS with mol. wt. above the threshold, 25 kDa, prevents the formation of an exponential growth regime and addn. of 10 mol % suppresses the influence of low mol. wt. PSS on film buildup.
- 38Lavalle, P.; Picart, C.; Mutterer, J.; Gergely, C.; Reiss, H.; Voegel, J.-C.; Senger, B.; Schaaf, P. Modeling the buildup of polyelectrolyte multilayer films having exponential growth. J. Phys. Chem. B 2004, 108, 635– 648, DOI: 10.1021/jp035740jGoogle Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXps1ymtLc%253D&md5=f249cabd2bbdc4c61904c63dd4d4c931Modeling the Buildup of Polyelectrolyte Multilayer Films Having Exponential GrowthLavalle, Philippe; Picart, Catherine; Mutterer, Jerome; Gergely, Csilla; Reiss, Howard; Voegel, Jean-Claude; Senger, Bernard; Schaaf, PierreJournal of Physical Chemistry B (2004), 108 (2), 635-648CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)Two types of polyelectrolyte multilayer films have been reported in the literature. These are (i) films whose mass and thickness increase linearly as the no. of deposited bilayers increases and (ii) films that grow exponentially. We present a model for the buildup of exponentially growing films that allows a discussion of the behavior of them in a unified manner. This model is based on the diffusion both in and out the whole film of part of the chains of at least one of the polyelectrolytes constituting the multilayer. In short, the film is brought into contact with the soln. of polyelectrolytes that are able to diffuse into the film. Inside of the film, chains of this polyelectrolyte constitute the "free" chains. At the subsequent rinsing step, some of them diffuse outward from the film. The remaining chains leave the film as it is brought into contact further with the polyelectrolyte soln. of opposite charge. As the "free" chains reach the film/soln. interface, they are complexed by the polyelectrolytes of opposite charge. These complexes, which are composed of both types of polyelectrolytes, contribute to the formation of the addnl. mass of the multilayer. The model relies on the evaluation of the electrostatic potential in the film within the framework of the Debye-Hueckel approxn. and takes into consideration the Donnan effect, which is due to noncompensated fixed charges in the film. It also includes the situation where none of the polyelectrolytes diffuse within the multilayer, in which case the film grows linearly. The model predicts the existence of a free-energy barrier that prevents total diffusion of any "free" polyelectrolyte outward from the film during a rinsing step, following contact with a polyelectrolyte soln. It also predicts that usually only one of the two polyelectrolytes that comprise the film diffuses readily into it. Both polyelectrolytes that comprise the film can diffuse "into" and "out of" the multilayer only when the concn. of noncompensated fixed charges within the film is very small. Several predictions of the model are discussed in the light of exptl. results that have already been published or are new.
- 39Kern, W. The evolution of silicon wafer cleaning technology. J. Electrochem. Soc. 1990, 137, 1887– 1892, DOI: 10.1149/1.2086825Google Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXkvVyrsbc%253D&md5=7eff60d2c0652358af90ef1a07bdc48fThe evolution of silicon wafer cleaning technologyKern, WernerJournal of the Electrochemical Society (1990), 137 (6), 1887-92CODEN: JESOAN; ISSN:0013-4651.A review with 70 refs. is given on the Si wafers cleaning.
- 40Decher, G.; Eckle, M.; Schmitt, J.; Struth, B. Layer-by-layer assembled multicomposite films. Curr. Opin. Colloid Interface Sci. 1998, 3, 32– 39, DOI: 10.1016/S1359-0294(98)80039-3Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXhslChtbc%253D&md5=b8c08e3e3cc36dc2b08680a1d1da957aLayer-by-layer assembled multicomposite filmsDecher, Gero; Eckle, Michel; Schmitt, Johannes; Struth, BerndCurrent Opinion in Colloid & Interface Science (1998), 3 (1), 32-39CODEN: COCSFL; ISSN:1359-0294. (Current Chemistry)A review with 56 refs. Three topics in the field of layer-by-layer assembly have made significant progress recently: structural investigations on multilayers composed of strong flexible polyelectrolytes and the development of a model for compn. and architecture of films of this kind; the incorporation of enzymes in multilayers for either biosensing or multistep biocatalysis; and the investigation of electroluminescent properties of such films.
- 41Palik, E. D. Handbook of Optical Constants of Solids; Academic Press, 1998; Vol. 3.Google ScholarThere is no corresponding record for this reference.
- 42Cornelsen, M.; Helm, C. A.; Block, S. Destabilization of polyelectrolyte multilayers formed at different temperatures and ion concentrations. Macromolecules 2010, 43, 4300– 4309, DOI: 10.1021/ma9027883Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkslKmu7k%253D&md5=80f193c8ca80fffe0e53060f27c45f9aDestabilization of Polyelectrolyte Multilayers Formed at Different Temperatures and Ion ConcentrationsCornelsen, Matthias; Helm, Christiane A.; Block, StephanMacromolecules (Washington, DC, United States) (2010), 43 (9), 4300-4309CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Polyelectrolyte multilayers (PEMs) from poly(allylamine hydrochloride) (PAH) and sodium poly(styrenesulfonate) (PSS) are prepd. at different conditions and investigated in air with X-ray reflectivity. Beyond a crit. temp. the thickness per deposited polycation/polyanion bilayer and the surface roughness increase on heating the prepn. soln. With increasing NaCl concn. that crit. temp. decreases (40°C at 1 M down to 15°C at 3 M). Below the crit. temp. the film thickness shows no dependence on the deposition temp. Also, for ion concns. up to 3 M, the surface roughness is const. (1-1.5 nm). However, for films prepd. at 4 M the roughness increases on cooling, which is attributed to approaching the UCST at very high salt concns. AFM measurements in air show that the increased surface roughness is due to a random pattern of holes, whose sepn. is characterized by a single length scale, a behavior typical for spinodal decompn. The length scale exceeds 100 nm and depends on the prepn. conditions. Grains consisting of polyelectrolyte complexes with a size below 30 nm do not influence the surface roughness. It is suggested that the decompn. occurs during film drying since the film morphol. in water shows no decompn. pattern, even when the film is cooled.
- 43Wu, Z.; Bouklas, N.; Huang, R. Swell-induced surface instability of hydrogel layers with material properties varying in thickness direction. Int. J. Solids Struct. 2013, 50, 578– 587, DOI: 10.1016/j.ijsolstr.2012.10.022Google Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslCkurnJ&md5=2254210c6692942bf0213af754389fefSwell-induced surface instability of hydrogel layers with material properties varying in thickness directionWu, Zhigen; Bouklas, Nikolaos; Huang, RuiInternational Journal of Solids and Structures (2013), 50 (3-4), 578-587CODEN: IJSOAD; ISSN:0020-7683. (Elsevier Ltd.)Upon swelling in a solvent, a thin hydrogel layer on a rigid substrate may become unstable, developing various surface patterns. Recent exptl. studies have explored the possibilities to generate controllable surface patterns by chem. modifying the mol. structures of the hydrogel near the surface. In this paper, we present a theor. stability anal. for swelling of hydrogel layers with material properties varying in the thickness direction. As a specialization of the general procedure, hydrogel bilayers with different combinations of the material properties are examd. in details. For a soft-on-hard bilayer, the onset of surface instability is detd. by the short-wave limit, similar to a homogeneous layer. In contrast, for a hard-on-soft bilayer, a long-wave mode with a finite wavelength emerges as the crit. mode at the onset of surface instability, similar to wrinkling of an elastic thin film on a compliant substrate, and the crit. swelling ratio is much lower than that for a homogeneous hydrogel layer. A smooth transition of the crit. mode is predicted as the vol. fraction of the top layer changes, linking surface instability of a homogeneous layer to thin film wrinkling as two limiting cases. The results from the present study suggest that both the crit. condition and the instability mode depend sensitively on the variation of the material properties in the thickness direction of the hydrogel layer.
- 44Soltwedel, O.; Ivanova, O.; Nestler, P.; Müller, M.; Köhler, R.; Helm, C. A. Interdiffusion in polyelectrolyte multilayers. Macromolecules 2010, 43, 7288– 7293, DOI: 10.1021/ma101279qGoogle Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXpvVGnuro%253D&md5=0a23824fa9e5c75c681648973256d3daInterdiffusion in Polyelectrolyte MultilayersSoltwedel, Olaf; Ivanova, Oxana; Nestler, Peter; Mueller, Madlen; Koehler, Ralf; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2010), 43 (17), 7288-7293CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Using neutron reflectivity, the internal structure of polyelectrolyte multilayers is described on the nanoscale. Each film consists of a protonated and a deuterated block, built from x protonated and y deuterated polycation/polyanion bilayers, resp. The no. of bilayers N = x + y is kept const.; the position of the interface between the blocks is varied systematically. The polyanion is poly(styrenesulfonate) (PSS), and the polycation is poly(allylamine hydrochloride) (PAH) or poly(diallyldimethylammonium chloride) (PDADMAC). Always, the first four to five bilayers are thinner than the av. bilayer thickness, but the three terminating bilayers are sometimes thicker. In the core zone, the bilayer thickness is const. The internal roughness is smallest next to the film/air interface and increases with the no. of bilayers away from the film/air interface. This suggests that each deposition step promotes the interdiffusion of the supporting layers. At the selected prepn. conditions, the internal roughness increases more for PDADMAC/PSS than for PAH/PSS; the diffusion consts. differ by 2 orders of magnitude.
- 45Collin, D.; Lavalle, P.; Garza, J. M.; Voegel, J.-C.; Schaaf, P.; Martinoty, P. Mechanical properties of cross-linked hyaluronic acid/poly-(L-lysine) multilayer films. Macromolecules 2004, 37, 10195– 10198, DOI: 10.1021/ma048683gGoogle Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVagtb3J&md5=02160f4b1753efd4d75bd2e34544a915Mechanical Properties of Cross-Linked Hyaluronic Acid/Poly-(L-lysine) Multilayer FilmsCollin, Dominique; Lavalle, Philippe; Garza, Juan Mendez; Voegel, Jean-Claude; Schaaf, Pierre; Martinoty, PhilippeMacromolecules (2004), 37 (26), 10195-10198CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Piezo-rheometer was used to detn. the complex shear modulus of hyaluronic acid/poly(L-lysine) multilayer film crosslinked with 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide in the presence of N-hydroxysulfosuccinimide.
- 46Ahrens, H.; orster, S. F.; Helm, C. A. Charged polymer brushes: counterion incorporation and scaling relations. Phys. Rev. Lett 1998, 81, 4172– 4175, DOI: 10.1103/PhysRevLett.81.4172Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntFyksbg%253D&md5=25ef5576cb9470561bba544720bacd10Charged Polymer Brushes: Counterion Incorporation and Scaling RelationsAhrens, Heiko; Forster, Stephan; Helm, Christiane A.Physical Review Letters (1998), 81 (19), 4172-4175CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Amphiphilic block copolymers consisting of a fluid hydrophobic and a polyelectrolyte part form monolayers at the air/water interface. With x-ray reflectivity it is shown that the hydrophobic block is a nm-thick melt, while the polyelectrolyte forms an osmotically swollen brush of const. thickness, independent of grafting d. and with stoichiometric counter ion incorporation. Only at high salt conditions (above 0.1 M), the brush shrinks and the thickness scales with the mol. area and the salt concn. (cor. for excluded vol. interactions) with an exponent -1/3.
- 47Ballauff, M.; Borisov, O. Polyelectrolyte brushes. Curr. Opin. Colloid Interface Sci. 2006, 11, 316– 323, DOI: 10.1016/j.cocis.2006.12.002Google Scholar47https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsFCksrc%253D&md5=2a303abd40a41d68fb3600f842fec9e4Polyelectrolyte brushesBallauff, Matthias; Borisov, OlegCurrent Opinion in Colloid & Interface Science (2006), 11 (6), 316-323CODEN: COCSFL; ISSN:1359-0294. (Elsevier B.V.)A review. Recent progress made in the field of polyelectrolyte brushes is reviewed. These systems consist of long polyelectrolyte chains that are grafted densely to planar or curved surfaces. The main feature of all polyelectrolyte brushes is the strong confinement of the counterions within the brush layer. The high osmotic pressure which is thus built up explains the unusual features of these systems. Here we focus on the most recent exptl. developments which are rationalized on the basis of existing theor. predictions and opens new challenging problems. In particular, we shall discuss briefly the exptl. systems used for comparing theory and expt. lately. Moreover, we review various aspects related to the exptl. anal. of polyelectrolyte brushes. As a final point, we survey trends in recent applications which demonstrate that polyelectrolyte brushes have an excellent prospect for future nanotechnol.
- 48Raviv, U.; Giasson, S.; Kampf, N.; Gohy, J.-F.; Jérôme, R.; Klein, J. Lubrication by charged polymers. Nature 2003, 425, 163– 165, DOI: 10.1038/nature01970Google Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXntFCitr0%253D&md5=1b160b605085336ceb4d9de080b76fe9Lubrication by charged polymersRaviv, Uri; Giasson, Suzanne; Kampf, Nir; Gohy, Jean-Francois; Jerome, Robert; Klein, JacobNature (London, United Kingdom) (2003), 425 (6954), 163-165CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Long-ranged forces between surfaces in a liq. control effects from colloid stability to biolubrication, and can be modified either by steric factors due to flexible polymers, or by surface charge effects. In particular, neutral polymer brushes' may lead to a massive redn. in sliding friction between the surfaces to which they are attached, whereas hydrated ions can act as extremely efficient lubricants between sliding charged surfaces. Here we show that brushes of charged polymers (polyelectrolytes) attached to surfaces rubbing across an aq. medium result in superior lubrication compared to other polymeric surfactants. Effective friction coeffs. with polyelectrolyte brushes in water are lower than about 0.0006-0.001 even at low sliding velocities and at pressures of up to several atmospheres (typical of those in living systems). We attribute this to the exceptional resistance to mutual interpenetration displayed by the compressed, counterion-swollen brushes, together with the fluidity of the hydration layers surrounding the charged, rubbing polymer segments. Our findings may have implications for biolubrication effects, which are important in the design of lubricated surfaces in artificial implants, and in understanding frictional processes in biol. systems.
- 49Gorelik, T. E. Electron Pair-Distribution Function (ePDF) Analysis. https://www.uni-ulm.de/fileadmin/website_uni_ulm/hrem/Outreach/ePDF_lecture_notes.pdf.Google ScholarThere is no corresponding record for this reference.
- 50Als-Nielsen, J.; Jacquemain, D.; Kjaer, K.; Leveiller, F.; Lahav, M.; Leiserowitz, L. Principles and applications of grazing incidence x-ray and neutron scattering from ordered molecular monolayers at the air-water interfac. Phys. Rep. 1994, 246 (5), 251– 313, DOI: 10.1016/0370-1573(94)90046-9Google Scholar51https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXisVartb8%253D&md5=7bf97a0613c5a456a6b9f73790410237Principles and applications of grazing incidence x-ray and neutron scattering from ordered molecular monolayers at the air-water interfaceAls-Nielsen, Jens; Jacquemain, Didier; Kjaer, Kristian; Leveiller, Franck; Lahav, Meir; Leiserowitz, LesliePhysics Reports (1994), 246 (5), 251-313CODEN: PRPLCM; ISSN:0370-1573.A review on well collimated, high intensity synchrotron x-ray sources and the consequent development of surface-specific x-ray diffraction and fluorescence techniques which recently have revolutionized the study of Langmuir monolayers of various amphiphiles (amino acids, alcs., carboxylic acids, phospholipids, etc.) at the air-liq. interface. These methods allow for the 1st time the detn. of the in-plane and vertical structure of such monolayers with a resoln. approaching the at. level. These methods include grazing incidence x-ray diffraction, specular reflectivity, Bragg rods, standing waves and surface fluorescence techniques. ∼ 146 Refs.
Cited By
This article is cited by 9 publications.
- Amir Azinfar, Christiane A. Helm. Self-Patterning of Polyelectrolyte Multilayer Films: The Roles of PSS Molecular Weight, the Top Layer, and Post-Preparation Treatment. Macromolecules 2023, 56
(8)
, 3095-3109. https://doi.org/10.1021/acs.macromol.2c02476
- Li Xu, Zihan Chu, Jianhua Zhang, Tingwei Cai, Xingxing Zhang, Yinzhao Li, Hailong Wang, Xiaochen Shen, Raymond Cai, Haifeng Shi, Chunyin Zhu, Jia Pan, Donghui Pan. Steric Effects in the Deposition Mode and Drug-Delivering Efficiency of Nanocapsule-Based Multilayer Films. ACS Omega 2022, 7
(34)
, 30321-30332. https://doi.org/10.1021/acsomega.2c03591
- Zheng Cao, Yang Zhang, Zili Luo, Wenjun Li, Tao Fu, Wang Qiu, Zhirong Lai, Junfeng Cheng, Haicun Yang, Wenzhong Ma, Chunlin Liu, Louis C. P. M. de Smet. Construction of a Self-Assembled Polyelectrolyte/Graphene Oxide Multilayer Film and Its Interaction with Metal Ions. Langmuir 2021, 37
(41)
, 12148-12162. https://doi.org/10.1021/acs.langmuir.1c02058
- Slaven Jurić, Marija Sigurnjak Bureš, Kristina Vlahoviček-Kahlina, Katarina Sopko Stracenski, Goran Fruk, Nenad Jalšenjak, Luna Maslov Bandić. Chitosan-based layer-by-layer edible coatings application for the preservation of mandarin fruit bioactive compounds and organic acids. Food Chemistry: X 2023, 17 , 100575. https://doi.org/10.1016/j.fochx.2023.100575
- Konstantinos T. Kotoulas, Jack Campbell, Andre G. Skirtach, Dmitry Volodkin, Anna Vikulina. Surface Modification with Particles Coated or Made of Polymer Multilayers. Pharmaceutics 2022, 14
(11)
, 2483. https://doi.org/10.3390/pharmaceutics14112483
- Biswa P. Das, Marina Tsianou. Molecular Organization in Exponentially Growing Multilayer Thin Films Assembled with Polyelectrolytes and Clay. Polymers 2022, 14
(20)
, 4333. https://doi.org/10.3390/polym14204333
- Rakshith Boranna, Naik Parrikar Vishwaraj, Suman Pahal, Chandrika Thondagere Nataraj, Raviprasad Kogravalli Jagannath, Shivananju Bannur Nanjunda, Gurusiddappa R. Prashanth. Fast‐Dip Layer‐by‐Layer Self‐Assembly of Polyelectrolytes as a Low‐Cost Biosensing Platform. Macromolecular Chemistry and Physics 2022, 223
(15)
, 2200054. https://doi.org/10.1002/macp.202200054
- Vladislava A. Pigareva, Ivan N. Senchikhin, Anastasia V. Bolshakova, Andrey V. Sybachin. Modification of Polydiallyldimethylammonium Chloride with Sodium Polystyrenesulfonate Dramatically Changes the Resistance of Polymer-Based Coatings towards Wash-Off from Both Hydrophilic and Hydrophobic Surfaces. Polymers 2022, 14
(6)
, 1247. https://doi.org/10.3390/polym14061247
- Da Zhang, Qing‐Shuang Li, Zi‐Xuan Liang, Xia‐Chao Chen, Junran Hao, Juming Yao, Chun‐Xin Lu, Yahong Zhou, Lei Jiang. Laser‐Directed Foaming of Hydroplastic Polyelectrolyte Films toward Tunable Structures and Programmable Routes. Advanced Functional Materials 2022, 32
(8)
, 2107598. https://doi.org/10.1002/adfm.202107598
Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.
Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.
The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.
Recommended Articles
References
This article references 50 other publications.
- 1Nestler, P.; Paßvogel, M.; Helm, C. A. Influence of polymer molecular weight on the parabolic and linear growth regime of PDADMAC/PSS multilayers. Macromolecules 2013, 46, 5622– 5629, DOI: 10.1021/ma400333f1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVKqtbbI&md5=378b1f60c6954d740e2f7d1d78257c0dInfluence of Polymer Molecular Weight on the Parabolic and Linear Growth Regime of PDADMAC/PSS MultilayersNestler, Peter; Passvogel, Malte; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2013), 46 (14), 5622-5629CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)The buildup of polyelectrolyte multilayers was investigated in soln. with multiple angle null-ellipsometry. Polyanion poly(styrene sulfonate) (PSS) and polycation poly(diallyldimethylammonium) (PDADMAC) were adsorbed sequentially from 0.1 M NaCl soln. First the films grew parabolically. After Ntrans deposited PDADMAC/PSS layer pairs a transition from a parabolic to a linear growth occurred. For mol. wts. above a threshold (Mw(PSS) > 25 kDa and Mw(PDADMAC) > 80 kDa), Ntrans is 15, the thickness per layer pair in the linear growth regime was 12.3 nm. If either the PDADMAC or the PSS mol. wt. decreased below the threshold value, Ntrans either fell (for PDADMAC, lowest value obsd. is 8) or rose (for PSS, highest value obsd. 33), resp. Simultaneously, in the linear growth regime, the thickness per layer pair decreases (down to 4.3 nm) or rises (up to 25 nm). Furthermore, for low mol. wt. PSS, three growth regimes were obsd.: exponential, parabolic, and linear. The opposite effect of PDADMAC and PSS mol. wt. redn. was discussed in terms of persistence lengths and linear charge d. The data suggest that mol. wt. provides a way to control growth and internal structure of polyelectrolyte multilayers.
- 2Hong, J. D.; Lowack, K.; Schmitt, J.; Decher, G. Layer-by-layer deposited multilayer assemblies of polyelectrolytes and proteins: from ultrathin films to protein arrays. Prog. Colloid Polym. Sci. 1993, 93, 98– 102, DOI: 10.1007/bfb01184822https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXmvVKqu7k%253D&md5=b85d77093ea1a17198ccc457c964f277Layer-by-layer deposited multilayer assemblies of polyelectrolytes and proteins: From ultrathin films to protein arraysHong, J. D.; Lowack, K.; Schmitt, J.; Decher, G.Progress in Colloid & Polymer Science (1993), 93 (TRENDS IN COLLOID AN), 98-102CODEN: PCPSD7; ISSN:0340-255X.We have recently introduced a new method of creating ultrathin films of polyelectrolytes based on the electrostatic attraction between opposite charges. Multilayer assemblies are adsorbed in a layer-by-layer fashion from aq. solns. of the polymers. The total film thickness can easily be adjusted by varying the ionic strength of the soln. Here, we report on the temp. stability and the water content of the multilayer assemblies. Furthermore, we have extended our concept to the incorporation of protein layers into films of synthetic polyelectrolytes. The well established system biotin/streptavidin was used to construct such multilayers, also by biospecific recognition. Adsorption of streptavidin onto previously photostructured precursor films leads to the deposition of the protein on selected areas on the substrate. The films were investigated by SAXS, Fourier Transform IR Spectroscopy (FTIR), and by fluorescence microscopy.
- 3Ghostine, R. A.; Markarian, M. Z.; Schlenoff, J. B. Asymmetric growth in polyelectrolyte multilayers. J. Am. Chem. Soc. 2013, 135, 7636– 7646, DOI: 10.1021/ja401318m3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnsFarsbY%253D&md5=c9d6707849cc2c16b1063e79d5ee5f7aAsymmetric Growth in Polyelectrolyte MultilayersGhostine, Ramy A.; Markarian, Marie Z.; Schlenoff, Joseph B.Journal of the American Chemical Society (2013), 135 (20), 7636-7646CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Radioactive counterions were used to track the ratio of pos. to neg. polymer repeat units within a polyelectrolyte multilayer made from poly(diallyldimethylammonium chloride), PDADMAC, and poly(styrene sulfonate), PSS. For this widely employed pair of "linearly" assembled polyelectrolytes it was found that the accepted model of charge overcompensation for each layer is incorrect. In fact, overcompensation at the surface occurs only on the addn. of the polycation, whereas PSS merely compensates the PDADMAC. After the assembly of about a dozen layers, excess pos. sites begin to accrue in the multilayer. Treating the surface as a reaction-diffusion region for pairing of polymer charges, a model profile was constructed. It is shown that different reaction-diffusion ranges of pos. and neg. polyelectrolyte charge lead to a blanket of glassy, stoichiometric complex growing on top of a layer of rubbery, PDADMAC-rich complex. Though overcompensation and growth was highly asym. with respect to the layer no., entirely conventional "linear" assembly of the multilayer was obsd. The impact of asym. growth on various properties of multilayers is discussed.
- 4Fu, J.; Schlenoff, J. B. Driving forces for oppositely charged polyion association in aqueous solutions: enthalpic, entropic, but not electrostatic. J. Am. Chem. Soc. 2016, 138, 980– 990, DOI: 10.1021/jacs.5b118784https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVKmsr8%253D&md5=874988141924788617f898cdebcddb6aDriving Forces for Oppositely Charged Polyion Association in Aqueous Solutions: Enthalpic, Entropic, but Not ElectrostaticFu, Jingcheng; Schlenoff, Joseph B.Journal of the American Chemical Society (2016), 138 (3), 980-990CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Driving forces for assocn. between oppositely charged biol. or synthetic polymers in aq. soln. have long been identified as electrostatic in origin. This attraction is broken down into an entropic component, due to loss of counterions, and an enthalpic component, stemming from Coulombic attraction between opposite charges. While the balance between entropic and enthalpic contributions shifts according to the conditions, the presence of exotherms or endotherms on mixing, though small, are viewed as signatures of Coulombic interactions which support theories of polyelectrolyte assocn. rooted in continuum electrostatics. Here, a head-to-head comparison is made between mechanisms based on electrostatics and those based on specific ion pairing, or ion exchange. Using a Hofmeister series of counterions for a common polycation, poly(diallyldimethylammonium), enthalpy changes on assocn. with poly(styrenesulfonate) are shown to derive from changes in water perturbation, revealed by Raman scattering studies of water O-H vibrations. The free energy for complexation is almost completely entropic over all salt concns.
- 5Costa, R. R.; Mano, J. F. Polyelectrolyte multilayered assemblies in biomedical technologies. Chem. Soc. Rev. 2014, 43, 3453– 3479, DOI: 10.1039/c3cs60393h5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmvFGmsb8%253D&md5=b962cc665bf249b8b207a913dfc2cab7Polyelectrolyte multilayered assemblies in biomedical technologiesCosta, Rui R.; Mano, Joao F.Chemical Society Reviews (2014), 43 (10), 3453-3479CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)Layer-by-layer (LbL) was first introduced as a surface modification technique based on the sequential spontaneous adsorption of at least two distinct materials onto planar substrates. In the last two decades, this technique has been expanded to the coating of more convoluted geometries with high levels of tailored functionalization or with structural purposes. In this review, the potential uses of LbL films in biomedical engineering based mainly on the assembly of polyelectrolytes are reviewed. Examples of recent developments are provided, from the modification of substrates to improve their biointegration or to add specialized properties, to the three-dimensional extrapolation of this technique to more complex structures for cell seeding, drug delivery devices, biosensors and customizable microreactors. Future strategies and opportunities are compared with current medical and laboratorial methodologies. Through them, it is expected that LbL will contribute greatly to the development of new functional devices with high perspectives of return for the administration of active agents, supports for cells in regenerative medicine and tissue engineering, biosensing and construction of microtissues and disease models in the lab.
- 6Richardson, J. J.; Björnmalm, M.; Caruso, F. Technology-driven layer-by-layer assembly of nanofilms. Science 2015, 348, aaa2491 DOI: 10.1126/science.aaa2491There is no corresponding record for this reference.
- 7Picart, C.; Mutterer, J.; Richert, L.; Luo, Y.; Prestwich, G.; Schaaf, P.; Voegel, J.-C.; Lavalle, P. Molecular basis for the explanation of the exponential growth of polyelectrolyte multilayers. Proc. Natl. Acad. Sci., U.S.A. 2002, 99, 12531– 12535, DOI: 10.1073/pnas.2024860997https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvFGiuro%253D&md5=ef85f688731df02b8970499ff36bb58aMolecular basis for the explanation of the exponential growth of polyelectrolyte multilayersPicart, C.; Mutterer, J.; Richert, L.; Luo, Y.; Prestwich, G. D.; Schaaf, P.; Voegel, J.-C.; Lavalle, P.Proceedings of the National Academy of Sciences of the United States of America (2002), 99 (20), 12531-12535CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The structure of poly(L-lysine) (PLL)/hyaluronan (HA) polyelectrolyte multilayers formed by electrostatic self-assembly is studied by using confocal laser scanning microscopy, quartz crystal microbalance, and optical waveguide lightmode spectroscopy. These films exhibit an exponential growth regime where the thickness increases exponentially with the no. of deposited layers, leading to micrometer thick films. Previously such a growth regime was suggested to result from an "in" and "out" diffusion of the PLL chains through the film during buildup, but direct evidence was lacking. The use of dye-conjugated polyelectrolytes now allows a direct three-dimensional visualization of the film construction by introducing fluorescent polyelectrolytes at different steps during the film buildup. We find that, as postulated, PLL diffuses throughout the film down into the substrate after each new PLL injection and out of the film after each PLL rinsing and further after each HA injection. As PLL reaches the outer layer of the film it interacts with the incoming HA, forming the new HA/PLL layer. The thickness of this new layer is thus proportional to the amt. of PLL that diffuses out of the film during the buildup step, which explains the exponential growth regime. HA layers are also visualized but no diffusion is obsd., leading to a stratified film structure. We believe that such a diffusion-based buildup mechanism explains most of the exponential-like growth processes of polyelectrolyte multilayers reported in the literature.
- 8Schönhoff, M. Layered polyelectrolyte complexes: physics of formation and molecular properties. J. Phys.: Condens. Matter 2003, 15, R1781– R1808, DOI: 10.1088/0953-8984/15/49/R01There is no corresponding record for this reference.
- 9Gopinadhan, M.; Ivanova, O.; Ahrens, H.; Günther, J.-U.; Steitz, R.; Helm, C. A. The influence of secondary interactions during the formation of polyelectrolyte multilayers: Layer thickness, bound water and layer interpenetration. J. Phys. Chem. B 2007, 111, 8426– 8434, DOI: 10.1021/jp067402z9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXks1Sjurg%253D&md5=33d6e3b0e0a740446c1c5743663cbac4The Influence of Secondary Interactions during the Formation of Polyelectrolyte Multilayers: Layer Thickness, Bound Water and Layer InterpenetrationGopinadhan, Manesh; Ivanova, Oxana; Ahrens, Heiko; Guenther, Jens-Uwe; Steitz, Roland; Helm, Christiane A.Journal of Physical Chemistry B (2007), 111 (29), 8426-8434CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)X-ray and neutron reflectivity methods were used to study the structure and compn. of polyelectrolyte multilayers from poly(allyl amine) (PAH) and poly(styrene sulfonate) (PSS), as a function of prepn. conditions (salt concn. and soln. temp., T). The onset of a temp. effect occurs at 0.05 M NaCl (Debye length ∼ 1 nm). At 1 M salt, the film thickness increases by a factor of 3 on heating the deposition soln. from 5 to 60°. The PAH/PSS bilayer thickness is independent of the kind of salt (NaCl or KCl), yet its compn. is different (more bound water for NaCl). At low T, the internal roughness is 33% of the bilayer thickness; it increases to 60% at high T. The roughening is accompanied by a total loss of bound water. The temp. at which roughening starts is a function of the kind of salt (50° for NaCl and 35° for KCl). The strong temp. dependence and the eventual loss of bound water mols. may be attributed to hydrophobic force; however, there is an isotope effect, since the loss of bound water is less pronounced in deuterated (D2O) layers.
- 10Dubas, S. T.; Schlenoff, J. B. Swelling and smoothing of polyelectrolyte multilayers by salt. Langmuir 2001, 17, 7725– 7727, DOI: 10.1021/la011209910https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXotV2msbY%253D&md5=54309398463563275c46f3ec9cfa356bSwelling and Smoothing of Polyelectrolyte Multilayers by SaltDubas, Stephan T.; Schlenoff, Joseph B.Langmuir (2001), 17 (25), 7725-7727CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The swelling mechanism was studied of polyelectrolyte multilayers on exposure to aq. solns. contg. NaCl using in situ at. force microscopy. The polyelectrolyte combinations used are poly(styrene sulfonate) (PSS)/poly(acrylic acid) (PAA); PSS/poly(diallyldimethylammonium) (PDADMA); and PSS/poly(allylamine hydrochloride) (PAH). The quasilinear swelling response, used to est. swelling coeffs. and equil., exhibits orders of magnitude of difference, depending on the polyelectrolyte pair constituting the multilayer. The surface roughness of as-made multilayers decreased significantly upon annealing in NaCl solns.
- 11Ginger, D. S.; Zhang, H.; Mirkin, C. A. The evolution of dip-pen nanolithography. Angew. Chem., Int. Ed. 2004, 43, 30– 45, DOI: 10.1002/anie.20030060811https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhsVelug%253D%253D&md5=17cccc48f10dd3193b5b42c25af90bbbThe evolution of dip-pen nanolithographyGinger, David S.; Zhang, Hua; Mirkin, Chad A.Angewandte Chemie, International Edition (2004), 43 (1), 30-35CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. The ability to tailor the chem. compn. and structure of a surface on the 1-100 nm length scale is important to researchers studying topics ranging from electronic conduction, to catalysis, to biol. recognition in nanoscale systems. Dip-pen nanolithog. (DPN) is a new scanning-probe based direct-write tool for generating such surface-patterned chem. functionality on the sub-100 nm length-scale, and it is a technique that is accessible to any researcher who can use an at. force microscope. This article introduces DPN and reviews the rapid growth of the field of DPN-related research over the past few years. Topics covered range from the development of new classes of DPN-compatible chem., to exptl. and theor. advances in the understanding of the processes controlling tip-substrate ink transport, to the implementation of micro-electromech. system (MEMS) based strategies for parallel DPN applications.
- 12Acikgoz, C.; Hempenius, M. A.; Huskens, J.; Vancso, G. J. Polymers in conventional and alternative lithography for the fabrication of nanostructures. Eur. Polym. J. 2011, 47, 2033– 2052, DOI: 10.1016/j.eurpolymj.2011.07.02512https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlWltLfO&md5=818f1ee86ae35965448e6e1b8f5b3f11Polymers in conventional and alternative lithography for the fabrication of nanostructuresAcikgoz, Canet; Hempenius, Mark A.; Huskens, Jurriaan; Vancso, G. JuliusEuropean Polymer Journal (2011), 47 (11), 2033-2052CODEN: EUPJAG; ISSN:0014-3057. (Elsevier Ltd.)A review. This review provides a survey of lithog. techniques and the resist materials employed with these techniques. The first part focuses on the conventional lithog. methods used to fabricate complex micro- and nano-structured surfaces. In the second part, emphasis is placed on patterning with unconventional lithog. techniques such as printing, molding, and embossing, and on their development into viable, high-resoln. patterning technologies.
- 13Jackson, E. A.; Hillmyer, M. A. Nanoporous membranes derived from block copolymers: from drug delivery to water filtration. ACS Nano 2010, 4, 3548– 3553, DOI: 10.1021/nn101400613https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptFOrsLw%253D&md5=4a15249f94179c9f3759623a5ec803bfNanoporous Membranes Derived from Block Copolymers: From Drug Delivery to Water FiltrationJackson, Elizabeth A.; Hillmyer, Marc A.ACS Nano (2010), 4 (7), 3548-3553CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. With nanoscale pores, high porosity, narrow pore size distributions, and tunable chem. and mech. properties, block copolymers hold tremendous potential as robust, efficient, and highly selective sepn. membranes. Recent work by Yang et al. illustrates how block copolymers can be employed in the prepn. of membranes for use in controlled, long-term, protein-delivery devices. Their work demonstrates that highly efficient and tunable sepns. are possible with block copolymer membranes. Although significant progress over the past 10 years has advanced the quality, efficacy, and applicability of such membranes, more work is required before benefits are realized for other demanding applications such as water purifn.
- 14Mörke, C.; Rebl, H.; Finke, B.; Dubs, M.; Nestler, P.; Airoudj, A.; Roucoules, V.; Schnabelrauch, M.; Körtge, A.; Anselme, K.; Helm, C. A.; Nebe, J. B. Abrogated cell contact guidance on amino-functionalized microgrooves. ACS Appl. Mater. Interfaces 2017, 9, 10461– 10471, DOI: 10.1021/acsami.6b1643014https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1czmsV2htw%253D%253D&md5=4154a91aacc0f3bd2cfe358230069edbAbrogated Cell Contact Guidance on Amino-Functionalized MicrogroovesMorke Caroline; Rebl Henrike; Nebe J Barbara; Finke Birgit; Dubs Manuela; Schnabelrauch Matthias; Nestler Peter; Helm Christiane A; Airoudj Aissam; Roucoules Vincent; Anselme Karine; Kortge AndreasACS applied materials & interfaces (2017), 9 (12), 10461-10471 ISSN:.Topographical and chemical features of biomaterial surfaces affect the cell physiology at the interface and are promising tools for the improvement of implants. The dominance of the surface topography on cell behavior is often accentuated. Striated surfaces induce an alignment of cells and their intracellular adhesion-mediated components. Recently, it could be demonstrated that a chemical modification via plasma polymerized allylamine was not only able to boost osteoblast cell adhesion and spreading but also override the cell alignment on stochastically machined titanium. In order to discern what kind of chemical surface modifications let the cell forget the underlying surface structure, we used an approach on geometric microgrooves produced by deep reactive ion etching (DRIE). In this study, we systematically investigated the surface modification by (i) methyl-, carboxyl-, and amino functionalization created via plasma polymerization processes, (ii) coating with the extracellular matrix protein collagen-I or immobilization of the integrin adhesion peptide sequence Arg-Gly-Asp (RGD), and (iii) treatment with an atmospheric pressure plasma jet operating with argon/oxygen gas (Ar/O2). Interestingly, only the amino functionalization, which presented positive charges at the surface, was able to chemically disguise the microgrooves and therefore to interrupt the microtopography induced contact guidance of the osteoblastic cells MG-63. However, the RGD peptide coating revealed enhanced cell spreading as well, with fine, actin-containing protrusions. The Ar/O2-functionalization demonstrated the best topography handling, e.g. cells closely attached even to features such as the sidewalls of the groove steps. In the end, the amino functionalization is unique in abrogating the cell contact guidance.
- 15Chen, L.; Yan, C.; Zheng, Z. Functional polymer surfaces for controlling cell behaviors. Mater. Today 2018, 21, 38– 59, DOI: 10.1016/j.mattod.2017.07.00215https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1GgsbbJ&md5=c29afe2704b42a288474dbb02efd8c24Functional polymer surfaces for controlling cell behaviorsChen, Lina; Yan, Casey; Zheng, ZijianMaterials Today (Oxford, United Kingdom) (2018), 21 (1), 38-59CODEN: MTOUAN; ISSN:1369-7021. (Elsevier Ltd.)A review. Thorough understanding of how to control cell behaviors including cell adhesion, orientation, migration and differentiation on an artificial surface is crit. in materials and life sciences such as advanced biomedical engineering, tissue engineering, and cell-based bioassay. In nature, extracellular matrix (ECM) plays an important role in controlling cell behaviors. It can not only provide the cells with mech. support but also profoundly affect cell functions such as metab., movement and transport process. Functional polymer surface exhibits superior advantages over many other materials for use as artificial ECM owing to its excellent mech. properties, abundant chem. species and remarkable capability to form various topog. surfaces. In particular, surface chem., mech. properties and topog. of these functional polymers are found to be three major parameters for effective control of cell behaviors. This paper comprehensively reviews the fundamental understanding of functional polymer surfaces for controlling cell behaviors. Different fabrication methods to achieve functional polymer surfaces and the parameters for effective control of cell behaviors are discussed. The future prospects and challenges particularly in cell biomedical engineering are also discussed at the end of this review paper.
- 16Rodríguez-Hernández, J. Wrinkled interfaces: Taking advantage of surface instabilities to pattern polymer surfaces. Prog. Polym. Sci. 2015, 42, 1– 41, DOI: 10.1016/j.progpolymsci.2014.07.00816https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlaht7rP&md5=9f3f32608cd666f3e1bde99caf95b1a5Wrinkled interfaces: Taking advantage of surface instabilities to pattern polymer surfacesRodriguez-Hernandez, JuanProgress in Polymer Science (2015), 42 (), 1-41CODEN: PRPSB8; ISSN:0079-6700. (Elsevier Ltd.)A review. The generation of nano-microstructured polymer film surfaces has been a challenge during the last decades. Advances in the fabrication of structured polymer surfaces to obtain micro and nano patterns have been accomplished following two different approaches, i.e., by adapting techniques, such as molding (embossing) or nano/microimprinting or by developing novel techniques including laser ablation, soft lithog. or laser scanning among others. Thus, higher resoln. capabilities are directly related with technol. advances. In contrast to the use of highly sophisticated tools required by the above mentioned techniques, surface instabilities produced by different mechanisms take advantage of the inherent properties of polymers to induce particular surface patterns. Some of the surface instabilities are well known since decades but novel and old known instability mechanisms have been only recently extended their use to pattern polymer surfaces. This recent interest relies on the rich and complex patterns obtained as a result of self-organizing processes that are rather difficult if not impossible to fabricate by using traditional patterning techniques. Among the approaches to obtain patterned interfaces by means of surface instabilities the formation of wrinkles is the most explored method and will be the center of this review. The fabrication approaches employed to induce wrinkle formation and the possibilities to fine tune the amplitude and period of the wrinkles, the functionality and their final morphol. are thoroughly described. Finally, an overview about the main applications in which buckled interfaces have been already employed or may have an impact in the near future is provided. Their use as templates, as flexible electronics, as supports with controlled wettability and/or adhesion or for biorelated applications are few of the fields in which the unique characteristics of wrinkled interfaces play distinguishing role.
- 17Bates, F. S. Polymer-polymer phase behavior. Science 1991, 251, 898– 905, DOI: 10.1126/science.251.4996.89817https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXhsVCgsrk%253D&md5=53fc355f97cf74f3bf5e17e2c427509fPolymer-polymer phase behaviorBates, Frank S.Science (Washington, DC, United States) (1991), 251 (4996), 898-905CODEN: SCIEAS; ISSN:0036-8075.A review with 57 refs. on basic factors governing polymer-polymer phase behavior with emphasis on linear homopolymer blends and diblock copolymers as representative model mol. architectures. Equil. thermodn. and phase sepn. dynamics are reviewed and discussed.
- 18Halperin, A.; Tirrell, M.; Lodge, T. Tethered Chains in Polymer Microstructures. In Macromolecules: Synthesis, Order and Advanced Properties; Springer, 1992; pp 31– 71.There is no corresponding record for this reference.
- 19Luo, M.; Epps, T. H., III Directed block copolymer thin film self-assembly: emerging trends in nanopattern fabrication. Macromolecules 2013, 46, 7567– 7579, DOI: 10.1021/ma401112y19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlKktLvK&md5=a526bee6f345280e88eae099081c6ad4Directed Block Copolymer Thin Film Self-Assembly: Emerging Trends in Nanopattern FabricationLuo, Ming; Epps, Thomas H., IIIMacromolecules (Washington, DC, United States) (2013), 46 (19), 7567-7579CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)A review. Block copolymers have garnered significant attention in the past few decades due to their ability to self-assemble into nanoscale structures (∼10-100 nm), making them ideal for emerging nanotechnologies, such as nanolithog., nanotemplating, nanoporous membranes, and ultrahigh-d. storage media. Many of these applications require thin film geometries, in which the block copolymers form well-ordered nanostructures and/or precisely controlled domain orientations. In this perspective, we discuss recent progress toward techniques that achieve directed self-assembly of block copolymer thin films. Substrate prepatterning, nanoimprint lithog., mol. transfer printing, solvent treatment, and zone processing approaches are highlighted. Finally, we comment on recent developments in high-throughput and in situ characterization methods, and we provide future research directions for thin film nanostructure refinement.
- 20Cini, N.; Tulun, T.; Decher, G.; Ball, V. Step-by-step assembly of self-patterning polyelectrolyte films violating (almost) all rules of layer-by-layer deposition. J. Am. Chem. Soc. 2010, 132, 8264– 8265, DOI: 10.1021/ja102611q20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvFaktbc%253D&md5=8c76ba8f7d4546c87992bec9d500e1e6Step-by-Step Assembly of Self-Patterning Polyelectrolyte Films Violating (Almost) All Rules of Layer-by-Layer DepositionCini, Nejla; Tulun, Tulay; Decher, Gero; Ball, VincentJournal of the American Chemical Society (2010), 132 (24), 8264-8265CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Because of its versatility, the layer-by-layer (LBL) assembly method has become a popular tool for prepg. multimaterial films, yet astonishingly little is known about the fundamental rules governing their deposition. Here we show an unusual case of self-patterning LBL films made from poly(allylamine hydrochloride) and poly(sodium phosphate). In such films, both the film thickness and the film roughness increase linearly with the no. of deposition steps up to a thickness of ∼60 nm. Even more surprising is the fact that the adsorption of individual "layers" of polyanions and polycations proceeds without a regular inversion of the ζ potential and with the occurrence of a growth instability at ∼75 layers. These findings underline the need to reconsider the fundamentals of polyelectrolyte multilayer film deposition.
- 21Chen, X.-c.; Ren, K.-f.; Chen, J.-y.; Wang, J.; Zhang, H.; Ji, J. Self-wrinkling polyelectrolyte multilayers: construction, smoothing and the underlying mechanism. Phys. Chem. Chem. Phys. 2016, 18, 31168– 31174, DOI: 10.1039/C6CP05419F21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslSntbfN&md5=61e6b5b30486aa929aaad873ac596973Self-wrinkling polyelectrolyte multilayers: construction, smoothing and the underlying mechanismChen, Xia-chao; Ren, Ke-feng; Chen, Jia-yan; Wang, Jing; Zhang, He; Ji, JianPhysical Chemistry Chemical Physics (2016), 18 (45), 31168-31174CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Introducing wrinkling or rough features into substrates is of great practical significance to construct various functional surfaces. Due to the sensitivity of assembled units towards environmental stimuli, the internals of layer-by-layer films can be readily adjusted to generate various micro- and nanostructures. We previously described a self-roughening polyelectrolyte multilayer (PEM) to facilitate the introduction of surface microstructures. In the present work, the growth process of PEI/PAA multilayer films was investigated and the mean size of the surface microstructures was found to increase linearly with the film thickness. The spontaneous formation of these surface features can be attributed to swelling-induced film deformation during the assembling process, which is similar to the surface wrinkling of hydrogels undergoing a vol. phase transition. When exposed to satd. humidity, the internal stress as well as the surface microstructures can be diminished spontaneously, leading to a flat surface over the substrates. Given the effect of the underlying film thickness on the characteristic wavelength of the surface wrinkles, multiscale surface microstructures can be readily realized by means of spatially presetting the distribution of the film thickness.
- 22Ghostine, R. A.; Jisr, R. M.; Lehaf, A.; Schlenoff, J. B. Roughness and salt annealing in a polyelectrolyte multilayer. Langmuir 2013, 29, 11742– 11750, DOI: 10.1021/la401632x22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlyjsrfI&md5=59dff5407c4e1dc0fef4bd463ffa65a5Roughness and Salt Annealing in a Polyelectrolyte MultilayerGhostine, Ramy A.; Jisr, Rana M.; Lehaf, Ali; Schlenoff, Joseph B.Langmuir (2013), 29 (37), 11742-11750CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The surface roughness of polyelectrolyte multilayers made from poly-(diallyldimethylammonium chloride), PDADMAC, and poly-(styrene sulfonate), PSS, was measured as a function of film deposition conditions. For dry multilayers, the significant roughness which builds up for thicker films is much more apparent for multilayers terminated with PSS. Corresponding roughness for PDADMA-capped multilayers may be seen by imaging in situ under electrolyte. Roughness may be substantially reduced, but not eliminated, by annealing in salt. Annealing does not lead to loss of polyelectrolyte from the film, even under conditions where the salt concn. is high enough to place the film properties beyond the glass transition. Roughness does not correlate with the mol. wt. of the polyelectrolyte and is thus not caused by soln. or film polymer chain conformations. The wavelength of the roughness features is approx. proportional to film thickness, which supports a mechanism whereby roughness is generated by anisotropic swelling due to water and polyelectrolyte addn. in a manner similar to water uptake in hydrogels. Roughness is preserved by the glassy PSS layer and probably incorporated within the film as it grows.
- 23Witt, M. A.; Valenga, F.; Blell, R.; Dotto, M. E.; Bechtold, I. H.; Felix, O.; Pires, A. T.; Decher, G. Layer-by-layer assembled films composed of “charge matched” and “length matched” polysaccharides: self-patterning and unexpected effects of the degree of polymerization. Biointerphases 2012, 7, 64, DOI: 10.1007/s13758-012-0064-423https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslajtbzN&md5=ea057df3288065c4184b8cf3fa71b059Layer-by-layer assembled films composed of "charge matched" and "length matched" polysaccharides: self-patterning and unexpected effects of the degree of polymerizationWitt, Maria A.; Valenga, Francine; Blell, Rebecca; Dotto, Marta E. R.; Bechtold, Ivan H.; Felix, Olivier; Pires, Alfredo T. N.; Decher, GeroBiointerphases (2012), 7 (1-4), 64CODEN: BJIOBN; ISSN:1559-4106. (Springer)The functionalization of chitosan with carboxymethyl groups allows zwitterionic or anionic chitosan derivs. to be obtained as a function of the degree of substitution. Here, we show that polyelectrolyte multilayers of chitosan and carboxymethylchitosan can be assembled by "dipping" or "spraying" to form strongly hydrated films in which both the polyanion and polycation possess the same polymer backbone ("matched chemistries"). Such films grow rapidly to fairly large thickness in very few assembly steps, esp. in the case of "matched" charge densities, and at. force microscopy reveals the formation of surface patterns that are dependent on the deposition conditions and on the no. of layers. Interestingly, the influence of the molar masses of the polyelectrolyte pairs on the complex formation is somewhat counterintuitive, the stronger complexation occurring between polyanions and polycations of different ("non-matching") lengths.
- 24Tanaka, T.; Sun, S.-T.; Hirokawa, Y.; Katayama, S.; Kucera, J.; Hirose, Y.; Amiya, T. Mechanical instability of gels at the phase transition. Nature 1987, 325, 796– 798, DOI: 10.1038/325796a024https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXhtl2jtLg%253D&md5=1d0a090aae700114cb8fd7d69d119ecaMechanical instability of gels at the phase transitionTanaka, Toyoichi; Sun, Shao Tang; Hirokawa, Yoshitsugu; Katayama, Seiji; Kucera, John; Hirose, Yoshiharu; Amiya, TakayukiNature (London, United Kingdom) (1987), 325 (6107), 796-8CODEN: NATUAS; ISSN:0028-0836.The pattern formation on acrylamide-Na acrylate copolymer [25085-02-3] gels during swelling was interpreted in terms of mech. instability caused by opposing forces on the upper and lower gel layers, one free to expand and the other to remain unswollen. Anal. predictions that the wavelength of the pattern was proportional to the gel thickness while the crit. osmotic pressure was independent of the gel thickness agreed with exptl. results.
- 25Rubinstein, M.; Semenov, A. N. Dynamics of entangled solutions of associating polymers. Macromolecules 2001, 34, 1058– 1068, DOI: 10.1021/ma001304925https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXislyhtg%253D%253D&md5=6005c7833708fe6c7c9bef83d7b50c83Dynamics of Entangled Solutions of Associating PolymersRubinstein, Michael; Semenov, Alexander N.Macromolecules (2001), 34 (4), 1058-1068CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)The process of making and breaking reversible bonds between assocg. groups (stickers) controls the dynamics of assocg. polymers. We develop a theory of "sticky reptation" to model the dynamics of entangled solns. of assocg. polymers with many stickers per chain. At a high degree of assocn., there are very few unassocd. stickers. It is therefore very difficult for a sticker to find a new partner to assoc. with after breaking the bond with an old one. Typically a sticker returns to its old partner following an unsuccessful search for a new one, prolonging the effective lifetime of reversible bonds. In the sticky reptation model, the search for a new partner is restricted to a part of the tube confining the entangled chain. Another important effect is the increase of the fraction of the interchain assocns. at the expense of the intrachain ones with increasing polymer concn. The sticky reptation model predicts a very strong concn. dependence of viscosity in good agreement with expts.
- 26Seo, J.; Lutkenhaus, J. L.; Kim, J.; Hammond, P. T.; Char, K. Effect of the layer-by-layer (LbL) deposition method on the surface morphology and wetting behavior of hydrophobically modified PEO and PAA LbL films. Langmuir 2008, 24, 7995– 8000, DOI: 10.1021/la800906x26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXntlaru7Y%253D&md5=7d09fbc4cf2abc2f6f33771bf33cc8d2Effect of the Layer-by-Layer (LbL) Deposition Method on the Surface Morphology and Wetting Behavior of Hydrophobically Modified PEO and PAA LbL FilmsSeo, Jinhwa; Lutkenhaus, Jodie L.; Kim, Junoh; Hammond, Paula T.; Char, KookheonLangmuir (2008), 24 (15), 7995-8000CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)We demonstrate that the surface morphol. and surface-wetting behavior of layer-by-layer (LbL) films can be controlled using different deposition methods. Multilayer films based upon hydrogen-bonding interactions between hydrophobically modified poly(ethylene oxide) (HM-PEO) and poly(acrylic acid) (PAA) have been prepd. using the dip- and spin-assisted LbL methods. A three-dimensional surface structure in the dip-assisted multilayer films appeared above a crit. no. of layer pairs owing to the formation of micelles of HM-PEO in its aq. dipping soln. In the case of spin-assisted HM-PEO/PAA multilayer films, no such surface morphol. development was obsd., regardless of the layer pair no., owing to the limited rearrangement and aggregation of HM-PEO micelles during spin deposition. The contrasting surface morphologies of the dip- and spin-assisted LbL films have a remarkable effect on the wetting behavior of water droplets. The water contact angle of the dip-assisted HM-PEO/PAA LbL films reaches a max. at an intermediate layer pair no., coinciding with the crit. no. of layer pairs for surface morphol. development, and then decreases rapidly as the surface structure is evolved and amplified. In contrast, spin-assisted HM-PEO/PAA LbL films yield a nearly const. water contact angle due to the surface chem. compn. and roughness that is uniform independent of layer pair no. We also demonstrate that the multilayer samples prepd. using both the dip- and spin-assisted LbL methods were easily peeled away from any type of substrate to yield free-standing films; spin-assisted LbL films appeared transparent, while dip-assisted LbL films were translucent.
- 27Sill, A.; Nestler, P.; Weltmeyer, A.; Paßvogel, M.; Neuber, S.; Helm, C. A. Polyelectrolyte Multilayer Films from Mixtures of Polyanions: Different Compositions in Films and Deposition Solutions. Macromolecules 2020, 53, 7107– 7118, DOI: 10.1021/acs.macromol.0c0108927https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsFehtLfK&md5=a5035c6a59bd5d1ab34ed5433880c69bPolyelectrolyte Multilayer Films from Mixtures of Polyanions: Different Compositions in Films and Deposition SolutionsSill, Annekatrin; Nestler, Peter; Weltmeyer, Antonia; Passvogel, Malte; Neuber, Sven; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2020), 53 (16), 7107-7118CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Polyelectrolyte multilayers are usually prepd. from polydisperse polyelectrolytes. It is desirable to measure and control multilayer compn. when it deviates from the deposition soln. With neutron reflectivity, multilayers prepd. from PDADMA and binary mixts. of long deuterated PSSdlong (80.8 kDa) and short protonated PSSshort (10.6 kDa) were investigated. A small amt. of PSSlong in the deposition soln. led to a disproportionate increase of PSSlong in the film, and completely suppressed the exponential growth regime. Adsorption kinetics were studied with in situ ellipsometry: (i) During adsorption of a PSS layer, the PSSlong fraction increased with adsorption time; PSSshort could desorb, while PSSlong adsorbed irreversibly. (ii) During adsorption of a PDADMA layer, a fast thickness increase was followed by a slow thickness decrease. This was attributed to the formation of PDADMA/PSSshort complexes, which eventually desorbed. The desorbed thickness depended on the no. of layers deposited. The mechanism of layer formation is attributed to the asym. growth of PDADMA/PSS multilayers, as supported by the adsorption kinetics of multilayers prepd. from one kind of PSS.
- 28Akkaoui, K.; Yang, M.; Digby, Z. A.; Schlenoff, J. B. Ultraviscosity in entangled polyelectrolyte complexes and coacervates. Macromolecules 2020, 53, 4234– 4246, DOI: 10.1021/acs.macromol.0c0013328https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXpt1KqsrY%253D&md5=bbba259587a28e0d2de024ae3181840aUltraviscosity in Entangled Polyelectrolyte Complexes and CoacervatesAkkaoui, Khalil; Yang, Mo; Digby, Zachary A.; Schlenoff, Joseph B.Macromolecules (Washington, DC, United States) (2020), 53 (11), 4234-4246CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)The spontaneous assocn. of oppositely charged polyelectrolytes is an example of liq.-liq. phase sepn. The resulting hydrated polyelectrolyte complexes or coacervates, both termed "PECs", display a wide range of viscosities. In addn. to the usual dependence of viscosity on mol. wt. and vol. fraction expected for condensed neutral polymers, PECs also contain dense charge pairing between pos., Pol+, and neg., Pol-, repeat units. These "stickers" slow polymer chain dynamics on multiple length scales. Pol+Pol- charge pairs may be broken by the addn. of salt to solns. contacting PECs, reducing viscosity ("saloplasticity"). Here, the dynamics of matched pairs of a polycation, poly(methacryloylaminopropyltrimethylammonium chloride), and polyanion, sodium poly(methacrylate), with mol. wts. considerably above the entanglement concn., were measured as a function of temp. and salt concn. The dynamics of NaCl ions in PECs were also detd. and correlated to the segmental relaxation times, which control viscosity. A suite of relaxation times corresponding to ion, monomer, Pol+Pol- pair exchange, entanglement, and reptation was detd. or estd. The zero-shear viscosity, η0, was found to be an unusually strong function of mol. wt., with the scaling η0 ≈ M5. A polymer coil size, measured by small-angle neutron scattering, was used in concert with new quant. expressions to provide a good fit of theory to expt. for this unusual scaling.
- 29Sill, A.; Nestler, P.; Azinfar, A.; Helm, C. A. Tailorable Polyanion Diffusion Coefficient in LbL Films: The Role of Polycation Molecular Weight and Polymer Conformation. Macromolecules 2019, 52, 9045– 9052, DOI: 10.1021/acs.macromol.9b0176129https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitFCit7rK&md5=a9227e4d9c456819a9c3ef93c003aba1Tailorable Polyanion Diffusion Coefficient in LbL Films: The Role of Polycation Molecular Weight and Polymer ConformationSill, Annekatrin; Nestler, Peter; Azinfar, Amir; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2019), 52 (22), 9045-9052CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Assembly of oppositely charged macromols. (proteins, DNA, polyelectrolytes) is often used for surface modification and functionalization. Yet, it remains a challenge to control the position and mobility of the mols. within the assembly. Using polyelectrolyte multilayers as model systems, we study the diffusion const. of the polyanion PSS. DPSS could be varied by 5 orders of magnitude. Two parameters were found to be important: (i) the conformation of the polyelectrolytes and (ii) the mol. wt. of the polycation (Mw(PDADMA)); the latter was the dominant parameter. Independent of conformation, by increasing Mw(PDADMA), DPSS decreased by at least 3 orders of magnitude when Mw(PDADMA) increased by a factor of seven. The decrease was stronger than predicted by any scaling law; it was either exponential or abrupt after DPSS was almost const. for low Mw(PDADMA). The polymer conformation was adjusted with the salt concn. in the prepn. soln. Flatter and less entangled chains led to an increase in DPSS. These findings on the time dependence of the internal structure of assemblies are discussed in the context of network theory.
- 30Hoogeveen, N.; Stuart, M. C.; Fleer, G.; Böhmer, M. Formation and stability of multilayers of polyelectrolytes. Langmuir 1996, 12, 3675– 3681, DOI: 10.1021/la951574y30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XjvFWksLw%253D&md5=03926b7941609ba1f1c3e8fab5cc3e5dFormation and Stability of Multilayers of PolyelectrolytesHoogeveen, Nynke G.; Cohen Stuart, Martien A.; Fleer, Gerard J.; Boehmer, Marcel R.Langmuir (1996), 12 (15), 3675-3681CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Sequential addn. of anionic and cationic polyelectrolytes may lead to the formation of multilayers at a solid surface. The buildup of such multilayers is characterized by a stepwise increase of the adsorbed amt. and layer thickness and by alternating highly pos. and highly neg. values for the ζ-potential. The prime variables which det. the stability of these structures are the polymer charge and the ionic strength. Very stable multilayers are formed when both polymers are highly charged and when the ionic strength is low. For weakly stable multilayers complexation at the surface may first occur, followed by desorption of the complexes. For strongly charged polyelectrolytes the charge stoichiometry, which is not always 1:1, seems to be unique for each pair of polyelectrolytes; no influence of the substrate, of the pH, or of the ionic strength could be obsd.
- 31Dodoo, S.; Steitz, R.; Laschewsky, A.; von Klitzing, R. Effect of ionic strength and type of ions on the structure of water swollen polyelectrolyte multilayers. Phys. Chem. Chem. Phys. 2011, 13, 10318– 10325, DOI: 10.1039/c0cp01357a31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmtFyksr4%253D&md5=57421a26406ee81e86f97d03862df01aEffect of ionic strength and type of ions on the structure of water swollen polyelectrolyte multilayersDodoo, S.; Steitz, R.; Laschewsky, A.; von Klitzing, R.Physical Chemistry Chemical Physics (2011), 13 (21), 10318-10325CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)This study addresses the effect of ionic strength and type of ions on the structure and water content of polyelectrolyte multilayers. Polyelectrolyte multilayers of poly(sodium-4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC) prepd. at different NaF, NaCl and NaBr concns. have been investigated by neutron reflectometry against vacuum, H2O and D2O. Both thickness and water content of the multilayers increase with increasing ionic strength and increasing ion size. Two types of water were identified, "void water" which fills the voids of the multilayers and does not contribute to swelling but to a change in scattering length d. and "swelling water" which directly contributes to swelling of the multilayers. The amt. of void water decreases with increasing salt concn. and anion radius while the amt. of swelling water increases with salt concn. and anion radius. This is interpreted as a denser structure in the dry state and larger ability to swell in water (sponge) for multilayers prepd. from high ionic strengths and/or salt soln. of large anions. No exchange of hydration water or replacement of H by D was detected even after eight hours incubation time in water of opposing isotopic compn.
- 32Zerball, M.; Laschewsky, A.; von Klitzing, R. Swelling of polyelectrolyte multilayers: The relation between, surface and bulk characteristics. J. Phys. Chem. B 2015, 119, 11879– 11886, DOI: 10.1021/acs.jpcb.5b0435032https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlWmtbrF&md5=99c4ec5ba4baf38a70b0805933bd9b17Swelling of Polyelectrolyte Multilayers: The Relation Between, Surface and Bulk CharacteristicsZerball, Maximilian; Laschewsky, Andre; von Klitzing, RegineJournal of Physical Chemistry B (2015), 119 (35), 11879-11886CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)The odd-even effect, i.e., the influence of the outermost layer of polyelectrolyte multilayers (PEMs) on their swelling behavior, is investigated. For that purpose poly(styrene sodium sulfonate) (PSS)/poly(diallyl-dimethylammonium chloride) (PDADMAC) polyelectrolyte multilayers are studied in air with 1% relative humidity (RH), 30% RH, 95% RH, and in liq. water by ellipsometry, at. force microscopy (AFM), and X-ray reflectometry (XRR). Since the total amt. of water uptake in swollen PEMs is divided into two fractions, the void water and the swelling water, a correct evaluation of the odd-even effect is only possible if both fractions are examd. sep. In order to allow measuring samples over a larger thickness regime the investigation of a larger amt. of samples is required. Therefore, the concept of sepg. void water from swelling water using neutron reflectometry is for the first time transferred to ellipsometry. The subsequent anal. of swelling water, void water, and roughness revealed the existence of two types of odd-even effects: an odd-even effect which addresses only the surface of the PEM (surface-odd-even effect) and an odd-even effect which addresses also the bulk of the PEM (bulk-odd-even effect). The appearance of both effects is dependent on the environment; the surface-odd-even effect is only detectable in humid air while the bulk-odd-even effect is only detectable in liq. water. The bulk-odd-even effect is related to the osmotic pressure between the PEM and the surrounding water. A correlation between the amt. of void water and both odd-even effects is not found. The amt. of void water is independent of the terminated layer and the thickness of PEMs.
- 33de 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.2014.10.04433https://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.
- 34Han, L.; Mao, Z.; Wu, J.; Zhang, Y.; Gao, C. Influences of surface chemistry and swelling of salt-treated polyelectrolyte multilayers on migration of smooth muscle cells. J. R. Soc., Interface 2012, 9, 3455– 3468, DOI: 10.1098/rsif.2012.054634https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhvValu73F&md5=7d06f8cdf339acc95f7d55537fa53fc6Influences of surface chemistry and swelling of salt-treated polyelectrolyte multilayers on migration of smooth muscle cellsHan, Lulu; Mao, Zhengwei; Wu, Jindan; Zhang, Yuying; Gao, ChangyouJournal of the Royal Society, Interface (2012), 9 (77), 3455-3468CODEN: JRSICU; ISSN:1742-5689. (Royal Society)The cell migration plays a crucial role in a variety of physiol. and pathol. processes and can be regulated by the cell-substrate interactions. We found previously that the poly (sodium 4-styrenesulfonate) (PSS)/poly(diallyldimethylammonium) chloride (PDADMAC) multilayers post-treated in 1-5 M NaCl solns. result in continuous changes of their physicochem. properties such as thickness, chem. compn., surface charge, swelling ratio and wettability. In this study, the responses of human smooth muscle cells (SMCs) on these salt-treated multilayers, particularly the governing factors of cellular migration that offer principles for designing therapeutics and implants, were disclosed. The cell migration rate was slowest on the 3 M NaCl-treated multilayers, which was comparable with that on tissue culture plates, but it was highest on 5 M NaCl-treated multilayers. To elucidate the intrinsic mechanisms, cell adhesion, proliferation, adhesion and related gene expressions were further investigated. The SMCs preferred to attach, spread and proliferate on the PSS-dominated surfaces with well-organized focal adhesion and act in fibers, esp. on the 3 M NaCl-treated multilayers, while were kept round and showed low viability on the PDADMAC-dominated surfaces. The relative mRNA expression levels of adhesion-related genes such as fibronectin, laminin and focal adhesion kinase, and migration-related genes such as myosin IIA and Cdc42 were compared to explain the different cellular behaviors. These results reveal that the surface chem. and the swelling of the salt-treated multilayers govern the cell migration behaviors.
- 35Kim, B. J.; Choi, I. S.; Yang, S. H. Cytocompatible Coating of Yeast Cells with Antimicrobial Chitosan through Layer-by-Layer Assembly. Bull. Korean Chem. Soc. 2016, 37, 1850– 1853, DOI: 10.1002/bkcs.1096335https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1ejtrjF&md5=5449090b35cada3e86abb1a3afbef0c0Cytocompatible Coating of Yeast Cells with Antimicrobial Chitosan through Layer-by-Layer AssemblyKim, Beom Jin; Choi, Insung S.; Yang, Sung HoBulletin of the Korean Chemical Society (2016), 37 (11), 1850-1853CODEN: BKCSDE; ISSN:0253-2964. (Wiley-VCH Verlag GmbH & Co. KGaA)Cytocompatible Coating of Yeast Cells with Antimicrobial Chitosan through Layer-by-Layer Assembly.
- 36Mohamad, H. S.; Neuber, S.; Helm, C. A. Surface Forces of Asymmetrically Grown Polyelectrolyte Multilayers: Searching for the Charges. Langmuir 2019, 35, 15491– 15499, DOI: 10.1021/acs.langmuir.9b0178736https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhslWgs7zN&md5=08b98683f60000d3c9eb25f88d77603cSurface Forces of Asymmetrically Grown Polyelectrolyte Multilayers: Searching for the ChargesMohamad, Heba S.; Neuber, Sven; Helm, Christiane A.Langmuir (2019), 35 (48), 15491-15499CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)The surface forces of polyelectrolyte multilayer films are measured. Films are made from polyelectrolytes with different linear charge d., poly(diallyldiemethylammonium) (PDADMA) and poly(styrenesulfonate) (PSS). Films were prepd. at 0.1 M NaCl, and at this ionic strength the multilayer surfaces are flat, uncharged and partially hydrophobic. For PSS-terminated films on decrease of the ionic strength electrostatic forces are found. At the beginning of multilayer formation, in the parabolic growth regime, the surface charge d. is neg. When the multilayer thickness increases linearly with the no. of deposited layers, the surface charge d. is pos. and low (one charge per 200-400 nm2). This reversal of surface charge is due to excess PDADMA-monomers within the film, as expected from asym. multilayers. On diln., PDADMA terminated films show steric forces, chains protrude into the soln. and form a pseudobrush. The brush scales as a polyelectrolyte brush. The thickness of the pseudobrush is independent of the no. of deposited layers, with a low grafting d. (1900 nm2 per chain). We suggest a model of polyelectrolyte multilayer formation: PDADMA with its low linear charge d. adsorbs with loosely bound chains. Monovalent anions within the film provide an elec. neutral surface. When PSS adsorbs onto a PDADMA-terminated multilayer, PSS replaces monovalent anions and forms electrostatic monomer-monomer bonds. The bond formation occurs within the polyelectrolyte multilayer; no surface charge is found.
- 37Paßvogel, M.; Nestler, P.; Köhler, R.; Soltwedel, O.; Helm, C. A. Influence of Binary Polymer Mixtures on the Nonlinear Growth Regimes of Polyelectrolyte Multilayer Films. Macromolecules 2016, 49, 935– 949, DOI: 10.1021/acs.macromol.5b0167437https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVGms78%253D&md5=6b9da38e05eea8e36253e60ff9985bc4Influence of Binary Polymer Mixtures on the Nonlinear Growth Regimes of Polyelectrolyte Multilayer FilmsPassvogel, Malte; Nestler, Peter; Koehler, Ralf; Soltwedel, Olaf; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2016), 49 (3), 935-949CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)We report on ellipsometric studies of the nonlinear growth regimes of electrostatically assembled polyelectrolyte multilayer films under in situ conditions. Poly(styrenesulfonate) (PSS) and poly(diallylmethylammonium) (PDADMA) with different mol. wts. in 0.1 mol/L NaCl are used. Always, the linear growth is preceded by a parabolic growth regime. For films made from binary PDADMA mixts., the compns. in the film and the adsorption soln. are nearly identical. To explain these findings, a mol. model that describes the parabolic growth quant. is introduced. Neutron reflectivity of films prepd. from PSS mol. wt. above a threshold, >25 kDa, shows that its center of mass is vertically immobile, in both the parabolic and linear growth regimes. Below 25 kDa, the multilayer buildup starts with an exponential growth regime, and pronounced PSS interdiffusion is found with neutron reflectivity. The exponential buildup regime is extended on decrease of PSS mol. wt. For films made from binary PSS mixts., addn. of less than 1 mol % PSS with mol. wt. above the threshold, 25 kDa, prevents the formation of an exponential growth regime and addn. of 10 mol % suppresses the influence of low mol. wt. PSS on film buildup.
- 38Lavalle, P.; Picart, C.; Mutterer, J.; Gergely, C.; Reiss, H.; Voegel, J.-C.; Senger, B.; Schaaf, P. Modeling the buildup of polyelectrolyte multilayer films having exponential growth. J. Phys. Chem. B 2004, 108, 635– 648, DOI: 10.1021/jp035740j38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXps1ymtLc%253D&md5=f249cabd2bbdc4c61904c63dd4d4c931Modeling the Buildup of Polyelectrolyte Multilayer Films Having Exponential GrowthLavalle, Philippe; Picart, Catherine; Mutterer, Jerome; Gergely, Csilla; Reiss, Howard; Voegel, Jean-Claude; Senger, Bernard; Schaaf, PierreJournal of Physical Chemistry B (2004), 108 (2), 635-648CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)Two types of polyelectrolyte multilayer films have been reported in the literature. These are (i) films whose mass and thickness increase linearly as the no. of deposited bilayers increases and (ii) films that grow exponentially. We present a model for the buildup of exponentially growing films that allows a discussion of the behavior of them in a unified manner. This model is based on the diffusion both in and out the whole film of part of the chains of at least one of the polyelectrolytes constituting the multilayer. In short, the film is brought into contact with the soln. of polyelectrolytes that are able to diffuse into the film. Inside of the film, chains of this polyelectrolyte constitute the "free" chains. At the subsequent rinsing step, some of them diffuse outward from the film. The remaining chains leave the film as it is brought into contact further with the polyelectrolyte soln. of opposite charge. As the "free" chains reach the film/soln. interface, they are complexed by the polyelectrolytes of opposite charge. These complexes, which are composed of both types of polyelectrolytes, contribute to the formation of the addnl. mass of the multilayer. The model relies on the evaluation of the electrostatic potential in the film within the framework of the Debye-Hueckel approxn. and takes into consideration the Donnan effect, which is due to noncompensated fixed charges in the film. It also includes the situation where none of the polyelectrolytes diffuse within the multilayer, in which case the film grows linearly. The model predicts the existence of a free-energy barrier that prevents total diffusion of any "free" polyelectrolyte outward from the film during a rinsing step, following contact with a polyelectrolyte soln. It also predicts that usually only one of the two polyelectrolytes that comprise the film diffuses readily into it. Both polyelectrolytes that comprise the film can diffuse "into" and "out of" the multilayer only when the concn. of noncompensated fixed charges within the film is very small. Several predictions of the model are discussed in the light of exptl. results that have already been published or are new.
- 39Kern, W. The evolution of silicon wafer cleaning technology. J. Electrochem. Soc. 1990, 137, 1887– 1892, DOI: 10.1149/1.208682539https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXkvVyrsbc%253D&md5=7eff60d2c0652358af90ef1a07bdc48fThe evolution of silicon wafer cleaning technologyKern, WernerJournal of the Electrochemical Society (1990), 137 (6), 1887-92CODEN: JESOAN; ISSN:0013-4651.A review with 70 refs. is given on the Si wafers cleaning.
- 40Decher, G.; Eckle, M.; Schmitt, J.; Struth, B. Layer-by-layer assembled multicomposite films. Curr. Opin. Colloid Interface Sci. 1998, 3, 32– 39, DOI: 10.1016/S1359-0294(98)80039-340https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXhslChtbc%253D&md5=b8c08e3e3cc36dc2b08680a1d1da957aLayer-by-layer assembled multicomposite filmsDecher, Gero; Eckle, Michel; Schmitt, Johannes; Struth, BerndCurrent Opinion in Colloid & Interface Science (1998), 3 (1), 32-39CODEN: COCSFL; ISSN:1359-0294. (Current Chemistry)A review with 56 refs. Three topics in the field of layer-by-layer assembly have made significant progress recently: structural investigations on multilayers composed of strong flexible polyelectrolytes and the development of a model for compn. and architecture of films of this kind; the incorporation of enzymes in multilayers for either biosensing or multistep biocatalysis; and the investigation of electroluminescent properties of such films.
- 41Palik, E. D. Handbook of Optical Constants of Solids; Academic Press, 1998; Vol. 3.There is no corresponding record for this reference.
- 42Cornelsen, M.; Helm, C. A.; Block, S. Destabilization of polyelectrolyte multilayers formed at different temperatures and ion concentrations. Macromolecules 2010, 43, 4300– 4309, DOI: 10.1021/ma902788342https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkslKmu7k%253D&md5=80f193c8ca80fffe0e53060f27c45f9aDestabilization of Polyelectrolyte Multilayers Formed at Different Temperatures and Ion ConcentrationsCornelsen, Matthias; Helm, Christiane A.; Block, StephanMacromolecules (Washington, DC, United States) (2010), 43 (9), 4300-4309CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Polyelectrolyte multilayers (PEMs) from poly(allylamine hydrochloride) (PAH) and sodium poly(styrenesulfonate) (PSS) are prepd. at different conditions and investigated in air with X-ray reflectivity. Beyond a crit. temp. the thickness per deposited polycation/polyanion bilayer and the surface roughness increase on heating the prepn. soln. With increasing NaCl concn. that crit. temp. decreases (40°C at 1 M down to 15°C at 3 M). Below the crit. temp. the film thickness shows no dependence on the deposition temp. Also, for ion concns. up to 3 M, the surface roughness is const. (1-1.5 nm). However, for films prepd. at 4 M the roughness increases on cooling, which is attributed to approaching the UCST at very high salt concns. AFM measurements in air show that the increased surface roughness is due to a random pattern of holes, whose sepn. is characterized by a single length scale, a behavior typical for spinodal decompn. The length scale exceeds 100 nm and depends on the prepn. conditions. Grains consisting of polyelectrolyte complexes with a size below 30 nm do not influence the surface roughness. It is suggested that the decompn. occurs during film drying since the film morphol. in water shows no decompn. pattern, even when the film is cooled.
- 43Wu, Z.; Bouklas, N.; Huang, R. Swell-induced surface instability of hydrogel layers with material properties varying in thickness direction. Int. J. Solids Struct. 2013, 50, 578– 587, DOI: 10.1016/j.ijsolstr.2012.10.02243https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslCkurnJ&md5=2254210c6692942bf0213af754389fefSwell-induced surface instability of hydrogel layers with material properties varying in thickness directionWu, Zhigen; Bouklas, Nikolaos; Huang, RuiInternational Journal of Solids and Structures (2013), 50 (3-4), 578-587CODEN: IJSOAD; ISSN:0020-7683. (Elsevier Ltd.)Upon swelling in a solvent, a thin hydrogel layer on a rigid substrate may become unstable, developing various surface patterns. Recent exptl. studies have explored the possibilities to generate controllable surface patterns by chem. modifying the mol. structures of the hydrogel near the surface. In this paper, we present a theor. stability anal. for swelling of hydrogel layers with material properties varying in the thickness direction. As a specialization of the general procedure, hydrogel bilayers with different combinations of the material properties are examd. in details. For a soft-on-hard bilayer, the onset of surface instability is detd. by the short-wave limit, similar to a homogeneous layer. In contrast, for a hard-on-soft bilayer, a long-wave mode with a finite wavelength emerges as the crit. mode at the onset of surface instability, similar to wrinkling of an elastic thin film on a compliant substrate, and the crit. swelling ratio is much lower than that for a homogeneous hydrogel layer. A smooth transition of the crit. mode is predicted as the vol. fraction of the top layer changes, linking surface instability of a homogeneous layer to thin film wrinkling as two limiting cases. The results from the present study suggest that both the crit. condition and the instability mode depend sensitively on the variation of the material properties in the thickness direction of the hydrogel layer.
- 44Soltwedel, O.; Ivanova, O.; Nestler, P.; Müller, M.; Köhler, R.; Helm, C. A. Interdiffusion in polyelectrolyte multilayers. Macromolecules 2010, 43, 7288– 7293, DOI: 10.1021/ma101279q44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXpvVGnuro%253D&md5=0a23824fa9e5c75c681648973256d3daInterdiffusion in Polyelectrolyte MultilayersSoltwedel, Olaf; Ivanova, Oxana; Nestler, Peter; Mueller, Madlen; Koehler, Ralf; Helm, Christiane A.Macromolecules (Washington, DC, United States) (2010), 43 (17), 7288-7293CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Using neutron reflectivity, the internal structure of polyelectrolyte multilayers is described on the nanoscale. Each film consists of a protonated and a deuterated block, built from x protonated and y deuterated polycation/polyanion bilayers, resp. The no. of bilayers N = x + y is kept const.; the position of the interface between the blocks is varied systematically. The polyanion is poly(styrenesulfonate) (PSS), and the polycation is poly(allylamine hydrochloride) (PAH) or poly(diallyldimethylammonium chloride) (PDADMAC). Always, the first four to five bilayers are thinner than the av. bilayer thickness, but the three terminating bilayers are sometimes thicker. In the core zone, the bilayer thickness is const. The internal roughness is smallest next to the film/air interface and increases with the no. of bilayers away from the film/air interface. This suggests that each deposition step promotes the interdiffusion of the supporting layers. At the selected prepn. conditions, the internal roughness increases more for PDADMAC/PSS than for PAH/PSS; the diffusion consts. differ by 2 orders of magnitude.
- 45Collin, D.; Lavalle, P.; Garza, J. M.; Voegel, J.-C.; Schaaf, P.; Martinoty, P. Mechanical properties of cross-linked hyaluronic acid/poly-(L-lysine) multilayer films. Macromolecules 2004, 37, 10195– 10198, DOI: 10.1021/ma048683g45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVagtb3J&md5=02160f4b1753efd4d75bd2e34544a915Mechanical Properties of Cross-Linked Hyaluronic Acid/Poly-(L-lysine) Multilayer FilmsCollin, Dominique; Lavalle, Philippe; Garza, Juan Mendez; Voegel, Jean-Claude; Schaaf, Pierre; Martinoty, PhilippeMacromolecules (2004), 37 (26), 10195-10198CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Piezo-rheometer was used to detn. the complex shear modulus of hyaluronic acid/poly(L-lysine) multilayer film crosslinked with 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide in the presence of N-hydroxysulfosuccinimide.
- 46Ahrens, H.; orster, S. F.; Helm, C. A. Charged polymer brushes: counterion incorporation and scaling relations. Phys. Rev. Lett 1998, 81, 4172– 4175, DOI: 10.1103/PhysRevLett.81.417246https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntFyksbg%253D&md5=25ef5576cb9470561bba544720bacd10Charged Polymer Brushes: Counterion Incorporation and Scaling RelationsAhrens, Heiko; Forster, Stephan; Helm, Christiane A.Physical Review Letters (1998), 81 (19), 4172-4175CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Amphiphilic block copolymers consisting of a fluid hydrophobic and a polyelectrolyte part form monolayers at the air/water interface. With x-ray reflectivity it is shown that the hydrophobic block is a nm-thick melt, while the polyelectrolyte forms an osmotically swollen brush of const. thickness, independent of grafting d. and with stoichiometric counter ion incorporation. Only at high salt conditions (above 0.1 M), the brush shrinks and the thickness scales with the mol. area and the salt concn. (cor. for excluded vol. interactions) with an exponent -1/3.
- 47Ballauff, M.; Borisov, O. Polyelectrolyte brushes. Curr. Opin. Colloid Interface Sci. 2006, 11, 316– 323, DOI: 10.1016/j.cocis.2006.12.00247https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsFCksrc%253D&md5=2a303abd40a41d68fb3600f842fec9e4Polyelectrolyte brushesBallauff, Matthias; Borisov, OlegCurrent Opinion in Colloid & Interface Science (2006), 11 (6), 316-323CODEN: COCSFL; ISSN:1359-0294. (Elsevier B.V.)A review. Recent progress made in the field of polyelectrolyte brushes is reviewed. These systems consist of long polyelectrolyte chains that are grafted densely to planar or curved surfaces. The main feature of all polyelectrolyte brushes is the strong confinement of the counterions within the brush layer. The high osmotic pressure which is thus built up explains the unusual features of these systems. Here we focus on the most recent exptl. developments which are rationalized on the basis of existing theor. predictions and opens new challenging problems. In particular, we shall discuss briefly the exptl. systems used for comparing theory and expt. lately. Moreover, we review various aspects related to the exptl. anal. of polyelectrolyte brushes. As a final point, we survey trends in recent applications which demonstrate that polyelectrolyte brushes have an excellent prospect for future nanotechnol.
- 48Raviv, U.; Giasson, S.; Kampf, N.; Gohy, J.-F.; Jérôme, R.; Klein, J. Lubrication by charged polymers. Nature 2003, 425, 163– 165, DOI: 10.1038/nature0197048https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXntFCitr0%253D&md5=1b160b605085336ceb4d9de080b76fe9Lubrication by charged polymersRaviv, Uri; Giasson, Suzanne; Kampf, Nir; Gohy, Jean-Francois; Jerome, Robert; Klein, JacobNature (London, United Kingdom) (2003), 425 (6954), 163-165CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Long-ranged forces between surfaces in a liq. control effects from colloid stability to biolubrication, and can be modified either by steric factors due to flexible polymers, or by surface charge effects. In particular, neutral polymer brushes' may lead to a massive redn. in sliding friction between the surfaces to which they are attached, whereas hydrated ions can act as extremely efficient lubricants between sliding charged surfaces. Here we show that brushes of charged polymers (polyelectrolytes) attached to surfaces rubbing across an aq. medium result in superior lubrication compared to other polymeric surfactants. Effective friction coeffs. with polyelectrolyte brushes in water are lower than about 0.0006-0.001 even at low sliding velocities and at pressures of up to several atmospheres (typical of those in living systems). We attribute this to the exceptional resistance to mutual interpenetration displayed by the compressed, counterion-swollen brushes, together with the fluidity of the hydration layers surrounding the charged, rubbing polymer segments. Our findings may have implications for biolubrication effects, which are important in the design of lubricated surfaces in artificial implants, and in understanding frictional processes in biol. systems.
- 49Gorelik, T. E. Electron Pair-Distribution Function (ePDF) Analysis. https://www.uni-ulm.de/fileadmin/website_uni_ulm/hrem/Outreach/ePDF_lecture_notes.pdf.There is no corresponding record for this reference.
- 50Als-Nielsen, J.; Jacquemain, D.; Kjaer, K.; Leveiller, F.; Lahav, M.; Leiserowitz, L. Principles and applications of grazing incidence x-ray and neutron scattering from ordered molecular monolayers at the air-water interfac. Phys. Rep. 1994, 246 (5), 251– 313, DOI: 10.1016/0370-1573(94)90046-951https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXisVartb8%253D&md5=7bf97a0613c5a456a6b9f73790410237Principles and applications of grazing incidence x-ray and neutron scattering from ordered molecular monolayers at the air-water interfaceAls-Nielsen, Jens; Jacquemain, Didier; Kjaer, Kristian; Leveiller, Franck; Lahav, Meir; Leiserowitz, LesliePhysics Reports (1994), 246 (5), 251-313CODEN: PRPLCM; ISSN:0370-1573.A review on well collimated, high intensity synchrotron x-ray sources and the consequent development of surface-specific x-ray diffraction and fluorescence techniques which recently have revolutionized the study of Langmuir monolayers of various amphiphiles (amino acids, alcs., carboxylic acids, phospholipids, etc.) at the air-liq. interface. These methods allow for the 1st time the detn. of the in-plane and vertical structure of such monolayers with a resoln. approaching the at. level. These methods include grazing incidence x-ray diffraction, specular reflectivity, Bragg rods, standing waves and surface fluorescence techniques. ∼ 146 Refs.
Supporting Information
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.langmuir.1c01409.
AFM images of the self-patterned and flat films measured in water (Figure S1); power spectral-density profiles obtained by the FFT analysis of the images shown in Figure 2 (Figure S2); X-ray reflectivity curves and deduced electron density profiles of different films (Figure S3); the film thickness and surface roughness in dependence of the number of deposited polycation/polyanion bilayers (Figure S4); vertical profiles of various films imaged by electron microscopy, both PSSshort- and PDADMA-terminated (Figures S5 and S6, respectively); and the diameter of the cross-sectional area of the domains (Figure S7) (PDF)
Terms & Conditions
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.