Memory Effects of Diblock Copolymer Brushes and Mixed Brushes

Abstract

Memory effects of microphase segregation in diblock copolymer brushes and binary mixed homopolymer brushes exposed to solvents of different quality and selectivity are studied using Single-Chain-in-Mean-Field (SCMF) simulations. We gauge these memory effects by a fluctuation memory measure, reflecting the correlation between the quenched fluctuations of grafting points and the microphase-separated morphology, and a domain memory measure, quantifying the correlation between surface morphologies during cyclic exposure to different solvents. The fluctuation and domain memory measures are closely correlated, and both of them have their root in the broken translational symmetry of the distribution of grafting points. They become stronger upon increasing the fluctuations of the grafting points. The effects of solvent quality and selectivity, grafting density, and composition of brushes on the memory measures are discussed.