Phase transition in liquid crystal elastomer - a Monte Carlo study employing non-Boltzmann sampling

TL;DR

This study uses non-Boltzmann Monte Carlo methods to explore the isotropic-nematic phase transition in liquid crystal elastomers, revealing how coupling strength influences transition order, temperature, and nematic order scaling.

Contribution

It introduces a Monte Carlo approach to analyze phase transitions in liquid crystal elastomers considering complex interactions and coupling effects.

Findings

Transition is strongly first order with strong coupling.

Transition softens and temperature decreases with weaker coupling.

Nematic order scales nonlinearly with strain at low temperatures.

Abstract

We investigate Isotropic - Nematic transition in liquid crystal elastomers employing non-Boltzmann Monte Carlo techniques. We consider a lattice model of a liquid elastomer and Selinger-Jeon-Ratna Hamiltonian which accounts for homogeneous/inhomogeneous interactions among liquid crystalline units, interaction of local nematics with global strain, and with inhomogeneous external fields and stress. We find that when the local director is coupled strongly to the global strain the transition is strongly first order; the transition softens when the coupling becomes weaker. Also the transition temperature decreases with decrease of coupling strength. Besides we find that the nematic order scales nonlinearly with global strain especially for strong coupling and at low temperatures.