Dynamics of nematic elastomers

TL;DR

This paper investigates the low-frequency, long-wavelength dynamics of nematic elastomers using two dynamic theories, revealing similarities to liquid crystal behavior and extending nematohydrodynamics to elastomers.

Contribution

It introduces two related dynamic models for nematic elastomers, one describing pure hydrodynamics and the other extending nematohydrodynamics to include director dynamics.

Findings

Sound modes in soft elastomers resemble those in columnar liquid crystals.

The models capture slow modes beyond the hydrodynamic limit.

The study provides a theoretical framework for nematic elastomer dynamics.

Abstract

We study the low-frequency, long-wavelength dynamics of soft and semi-soft nematic elastomers using two different but related dynamic theories. Our first formulation describes the pure hydrodynamic behavior of nematic elastomers in which the nematic director has relaxed to its equilibrium value in the presence of strain. We find that the sound-modes structure for soft elastomers is identical to that of columnar liquid crystals. Our second formulation generalizes the derivation of the equations of nematohydrodynamics by the Harvard group to nematic elastomers. It treats the director explicitly and describes slow modes beyond the hydrodynamic limit.