Pattern Formation in Phase-Separating Gels with Spontaneous Shear

TL;DR

This paper investigates how patterns form in phase-separating gels that also undergo orientational ordering, revealing different morphologies depending on the coupling strength, through 2D simulations of a nonlinear elastic model.

Contribution

It introduces a minimal nonlinear elasticity model coupling density and anisotropy to simulate pattern formation in phase-separating, orientationally ordered gels.

Findings

Strong positive coupling leads to buckled, folded structures with topological defects.

Negative coupling results in droplet morphologies similar to liquid-liquid phase separation.

The study discusses potential realizations in nematic liquid-crystalline gels.

Abstract

We study pattern formation in gels undergoing simultaneous phase separation and orientational ordering. A 2D numerical simulation is performed using a minimal model of nonlinear elasticity with density-anisotropy coupling. For strong positive coupling, the collapsed phase elongates along the phase boundary and buckles, creating a folded structure with paired topological defects. For negative coupling, soft elasticity of the swollen phase causes a droplet morphology as in liquid-liquid phase separation. Their possible realizations in nematic liquid-crystalline gels are discussed.