Interaction between two polyelectrolyte brushes: a mesoscale modelling of the compression

Abstract

We report dissipative particle dynamics (DPD) simulations of two interacting polyelectrolyte brushes under athermal solvent conditions. The standard DPD model is modified by the addition of the electrostatic interactions and of the spring-spring repulsion to model entangled polyelectrolyte chains. The dependence of the brush height on the charge fraction is compared for a monolayer and a bilayer of polyelectrolyte brushes. We also report the effect of the compression on the structural properties of neutral and polyelectrolyte brushes using DPD simulations at fixed solvent chemical potential. At a given overlap between the opposing brushes, the polyelectrolyte brushes can support a larger load compared to neutral brushes. This is one of the factors that may explain the lubricant properties of polyelectrolyte brushes.