Dynamic Theory of Polydomain Liquid-Crystal Elastomers

TL;DR

This paper develops a dynamic theory explaining how the isotropic-nematic transition in liquid-crystal elastomers can naturally lead to polydomain structures with a characteristic length scale, without requiring quenched disorder.

Contribution

The authors introduce a novel dynamic model for the isotropic-nematic transition that accounts for polydomain formation through a phase separation mechanism.

Findings

Polydomain structures can form dynamically during the transition.

The model predicts a characteristic length scale for the domains.

Polydomain formation can occur without quenched disorder.

Abstract

When liquid-crystal elastomers are prepared without any alignment, disordered polydomain structures emerge as the materials are cooled into the nematic phase. These polydomain structures have been attributed to quenched disorder in the cross-linked polymer network. As an alternative explanation, we develop a theory for the dynamics of the isotropic-nematic transition in liquid-crystal elastomers, and show that the dynamics can induce a polydomain structure with a characteristic length scale, through a mechanism analogous to the Cahn-Hilliard equation for phase separation.