Relaxational Dynamics and Compressional Properties of Polymer Brushes

Abstract

We run molecular dynamics simulations to study the relaxation dynamics of a single polydisperse brush in the short unentangled regime, and of a brush-bilayer system of different polydispersity indices to study its equilibrium pressure properties. We find an unexpected behaviour with the relaxation times, likely due to the effects of frozen disorder. As for the pressure of the bilayer system, we found that the characterization of the free energy by the number of interbrush contacts is a valid one. However, we found that the pressure for the same densities depended on the polydispersity index. Investigations led us to attribute this to chain-end effects, which were completely unaccounted for in the context of the mean field theory.