Authors Merlitz, H. ; Li, C. ; Wu, C.-X. ; Sommer, J.-U.
Title Polyelectrolyte brushes in external fields: molecular dynamics simulations and mean-field theory
Date 15.06.2015
Number 46841
Abstract A mean-field model is developed to predict the layer-thickness of sparse and salt-free polyelectrolyte brushes, exposed to an external electric field, which attracts the polyelectrolytes to the substrate. In molecular dynamics simulations, it is shown that a fraction of polymers collapses entirely to screen the charge of the substrate. The remaining brushes are then treated as field-free brushes at reduced grafting density. The mean-field model may thus be applied to field-free brushes, both in their osmotic and their weak charge regimes. It yields simple, closed equations for the brush height and for the partition of counterions in- and outside the brushes, and accurately reproduces simulation data of the collapse of the brushes during the crossover between both charge regimes.
Publisher Soft Matter
Citation Soft Matter 11 (2015) 5688-5696

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