Phase separation in soft repulsive polymer mixtures: foundation and implication for chromatin organization

TL;DR

This paper develops a super-coarse grained mean-field model for polymer mixtures to analyze phase separation, with implications for understanding chromatin organization in cell nuclei.

Contribution

It introduces a novel super-coarse grained description of polymers and explores phase separation behaviors, extending to mixtures with random copolymers relevant to chromatin.

Findings

Universal aspects of the miscibility phase diagram identified

Mean-field theory effectively predicts phase separation behaviors

Extension to random copolymer mixtures offers insights into chromatin organization

Abstract

Given the wide range of length scales, the analysis of polymer systems often requires coarse-graining, for which various levels of description may be possible depending on the phenomenon under consideration. Here, we provide a super-coarse grained description, where polymers are represented as a succession of mesosopic soft beads which are allowed to overlap with others. We then investigate the phase separation behaviors in a mixture of such homopolymers based on mean-field theory, and discuss universal aspects of the miscibility phase diagram in comparison with the numerical simulation. We also discuss an extension of our analysis to mixtures involving random copolymers, which might be interesting in the context of chromatin organization in a cell nucleus.