Internal structure of polyelectrolyte multilayer assemblies

Klitzing, Regine von

doi:10.1039/b607760a

Cited by 404 publications

(470 citation statements)

References 153 publications

(237 reference statements)

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“…In addition, most computer simulation studies have been based on top-down coarse-grained modeling approaches, characterized by rough approximations and a very limited connection with the microscopic properties of the system. For an overview about theoretical modeling and experimental work performed on PEMs and its open challenges the reader is addressed to recent literature 4,[9][10][11][12] and references therein.…”

Section: Introductionmentioning

confidence: 99%

Layer-by-Layer Formation of Oligoelectrolyte Multilayers: A Combined Experimental and Computational Study

et al. 2014

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For the first time, the combination of experimental preparation and results of fully atomistic simulations of an oligoelectrolyte multilayer (OEM) made of poly(diallyl dimethyl ammonium chloride)/poly(styrene sulfonate sodium salt) (PDADMAC/PSS) is presented. The layer-bylayer growth was carried out by dipping silica substrates in oligoelectrolyte solutions and was * To whom correspondence should be addressed † modeled by means of atomistic molecular dynamics simulations with a protocol that mimics the experimental procedure up to the assembly of four layers. Measurements of OEM thickness, surface roughness and amount of adsorbed oligoelectrolyte chains obtained from both approaches are compared. A good agreement between simulated and experimental results was found, with some deviations due to intrinsic limitations of both methods. However, the combination of information extracted from simulations to support the analysis of experimental data can overcome such restrictions and improve the interpretation of experimental results. On the other hand, processes dominated by slower kinetics, like the destabilization of adsorbed layers upon equilibration with the surrounding environment, are out of reach for the simulation modeling approach, but they can be investigated by monitoring in situ the oligoelectrolyte adsorption during the assembly process. This demonstrates how the synergistic use of simulation and experiments improves the knowledge of OEM properties down to the molecular scale.

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Section: Introductionmentioning

confidence: 99%

Layer-by-Layer Formation of Oligoelectrolyte Multilayers: A Combined Experimental and Computational Study

et al. 2014

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“…Now depending upon the used PEs, these multilayers can be erasable by some external stimuli such as a shift in pH [41][42][43] or by increasing the ionic strength [44,45]. For a weak PE system such as PAH/PAA, where the charge density depends on solution pH, a combination of both of these stimuli (low pH and high ionic strength) can add a trigger to sacrifice (remove) the PEM coating along with attached foulants, as shown previously [34].…”

Section: Introductionmentioning

confidence: 88%

Preparation of multifunctional hollow fiber nanofiltration membranes by dynamic assembly of weak polyelectrolyte multilayers

Ilyas

English

Aimar

et al. 2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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A B S T R A C TIn this work, we investigate the effect of preparation conditions for dynamic layer-by-layer (LbL) coating, to prepare multifunctional hollow fiber nanofiltration (NF) membranes. Dynamic coating was performed at constant pressure and at variable cross flow speeds. In this way, polyelectrolyte multilayers (PEMs) were formed of the weak polyelectrolytes poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH), on a negatively charged polyethersulfone ultrafiltration (UF) support. The resulting membrane performance was investigated and compared to membranes prepared by different methods (dip coating and dead end filtration), and it was found to be comparable. It was shown that PAH/ PAA multilayers can be fabricated reproducibly and homogenously using optimised dynamic LbL deposition conditions on single fiber module (surface area of 6.2 cm 2 ) as well as on a module of 15 fibers (surface area of 67 cm 2 ). Moreover, the approach of dynamic coating could be easily up scaled to coat existing UF modules. The prepared membranes reject the solutes on the basis of size exclusion and Donnan exclusion, retaining small organic solutes and divalent ions. Membranes terminated with PAA exhibit a low fouling tendency compared to membranes terminated with PAH and compared to the UF support membrane. Moreover, if severe membrane fouling would occur after prolonged use, the PEM coating, including any attached foulants can be removed by rinsing with a solution that combines a low pH and a high salinity (pH 3, 3 M). The surface of bovine serum albumin (BSA) fouled membranes were successfully cleaned at least twice, after which a new PEM coating could be re-applied by active coating.

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“…Surface molecular imprinted polyelectrolyte multilayer films (SmiLbL films) are based on the layer-by-layer self-assembly of oppositely charged polyelectrolytes [32][33][34][35] and have opened an established class of thin and structured nanomaterial that bears imprinted binding sites for the reversible binding and release of small organic molecules [36]. In such polymer films, the binding sites are located comparatively close to a surface, therefore solving the problem of long diffusion pathways and buried binding sites known from macroscopic molecular imprinted materials [37,38].…”

Section: Introductionmentioning

confidence: 99%

pH-Responsive Host–Guest Complexation in Pillar[6]arene-Containing Polyelectrolyte Multilayer Films

Nicolas

Zhang

et al. 2017

Polymers

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Abstract:A water-soluble, anionic pillar [6]arene derivative (WP6) is applied as monomeric building block for the layer-by-layer self-assembly of thin polyelectrolyte multilayer films, and its pH-dependent host-guest properties are employed for the reversible binding and release of a methylviologen guest molecule. The alternating assembly of anionic WP6 and cationic diazo resin (DAR) is monitored in-situ by a dissipative quartz crystal microbalance (QCM-D). In solution, the formation of a stoichiometric inclusion complex of WP6 and cationic methylviologen (MV) as guest molecule is investigated by isothermal titration calorimetry and UV-vis spectroscopy, respectively, and attributed to electrostatic interactions as primary driving force of the host-guest complexation. Exposure of WP6-containing multilayers to MV solution reveals a significant decrease of the resonance frequency, confirming MV binding. Subsequent release is achieved by pH lowering, decreasing the host-guest interactions. The dissociation of the host-guest complex, release of the guest from the film, as well as full reversibility of the binding event are identified by QCM-D. In addition, UV-vis data quantify the surface coverage of the guest molecule in the film after loading and release, respectively. These findings establish the pH-responsiveness of WP6 as a novel external stimulus for the reversible guest molecule recognition in thin films.

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Internal structure of polyelectrolyte multilayer assemblies

Cited by 404 publications

References 153 publications

Layer-by-Layer Formation of Oligoelectrolyte Multilayers: A Combined Experimental and Computational Study

Layer-by-Layer Formation of Oligoelectrolyte Multilayers: A Combined Experimental and Computational Study

Preparation of multifunctional hollow fiber nanofiltration membranes by dynamic assembly of weak polyelectrolyte multilayers

pH-Responsive Host–Guest Complexation in Pillar[6]arene-Containing Polyelectrolyte Multilayer Films

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