Theory of polyelectrolyte dendrigrafts

Abstract

A mean-field approach is used to analyze equilibrium conformations of polyelectrolyte dendrigrafts comprising ionically charged dendrons attached by focal points to a flexible linear backbone. Power law dependences for local structural parameters, cross-sectional thickness and intergraft distance, are derived as a function of grafting density and degree of branching of the dendrons. The cases of quenched and pH-sensitive ionization of the dendrons are considered. The finite extensibility of the backbone is taken into account. It is demonstrated that an increase in the degree of branching of the dendrons leads to a decrease in the dendrigraft thickness compared with that of the polyelectrolyte molecular brush with the same degree of polymerization of the side chains, while intergraft distance either increases or stays close to counter length of fully extended backbone spacer. The analytical mean-field theory predictions are confirmed by results of numerical self-consistent field modelling.