Polyelectrolyte Brushes: MD Simulation and SCF Theory

SZ He and H Merlitz and L Chen and JU Sommer and CX Wn, MACROMOLECULES, 43, 7845-7851 (2010).

DOI: 10.1021/ma101230v

Off-lattice molecular dynamics simulations are carried out to study fully charged polyelectrolyte brushes with salt, and a comparison with an off-lattice self-consistent field (SCF) theory including finite stretching and volume effects Biesheuvel et al. Macromolecules 2008, 41, 6254 is presented. The SCF approach is able to reproduce the brush heights at different grafting densities, salt concentrations, and chain lengths on a semiquantitative level. At high grafting densities, the density profiles obtained with both techniques exhibit a particularly close agreement, while at low densities systematic deviations between their shapes are observed. The approximation of local electroneutrality, which the SCF approach is based on, is studied, and its implications are discussed. In this context, the strengths and limitations of the SCF model are analyzed in detail.

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