Theory of Microphase Separation in Elastomers

TL;DR

This paper develops a phase-field model to understand microphase separation in solvent-swollen elastomers, revealing how elasticity influences domain formation and stability, with predictions aligning well with experimental observations.

Contribution

It introduces a novel phase-field model that captures the interplay between demixing and elasticity, explaining microphase morphology formation in elastomers.

Findings

Domain size depends on elastomer stiffness

Transition temperature varies with solvent content

Stable microphase morphologies are predicted and characterized

Abstract

Inspired by recent experiments, we present a phase-field model of microphase separation in an elastomer swollen with a solvent. The imbalance between the molecular scale of demixing and the mesoscopic scale beyond which elasticity operates produces effective long-range interactions, forming stable finite-sized domains. Our predictions concerning the dependence of the domain size and transition temperature on the stiffness of the elastomer are in good agreement with the experiments. Analytical phase diagrams, aided by numerical findings, capture the richness of the microphase morphologies, paving the way to create stable, patterned elastomers for various applications.