CONFORMATION OF SURFACE-BOUND POLYELECTROLYTES .2. A MONTE-CARLO STUDY OF MEDIUM-LENGTH LATTICE CHAINS

A combination of a Monte Carlo technique and mean-field theory is used to study the interaction of two planar surfaces bearing end-attached polyelectrolytes. The latter are modeled as flexible, linear chains whose self-avoiding configurations are superimposed on a tetrahedral lattice. Electrostatic interactions are taken into account via a mean-field potential that satisfies an extended Poisson–Boltzmann equation, while chain excluded volume effects are included via avoidance sampling of configurations. A mean-field potential energy expression is used to study the interaction of the two surfaces. Examples of the dependence of the monomer distribution, electrostatic potential, and the interaction potential on the effective polyelectrolyte charge, surface charge, and salt concentration are presented. The interaction potential acting between these two surfaces exhibits the influence of many competing effects arising from the presence of charged chains and is significantly different from either the interaction of surfaces with grafted neutral chains or the usual double-layer interaction between two charged planes. © 1990, American Chemical Society. All rights reserved.