Mechanical switching of ferro-electric rubber

TL;DR

This paper explores how mechanical and electrical stimuli can induce large strains and switch polarization in smectic C elastomers, revealing microstructures and ferro-electric behavior relevant for advanced material applications.

Contribution

It provides explicit analysis of strain induction mechanisms and microstructure configurations in Sm-C elastomers, including polarization reversal in chiral variants.

Findings

Strains up to twice the spontaneous shear can be mechanically or electrically induced.

Microstructures in Sm-C elastomers are characterized under various constraints.

Polarization in chiral Sm-C elastomers can be mechanically reversed depending on strain and geometry.

Abstract

At the A to C transition, smectic elastomers have recently been observed to undergo $\sim$35% spontaneous shear strains. We first explicitly describe how strains of up to twice this value could be mechanically or electrically induced in Sm-$C$ elastomers by rotation of the director on a cone around the layer normal at various elastic costs depending on constraints. Secondly, for typical sample geometries, we give the various microstructures in Sm-$C$ akin to those seen in nematic elastomers under distortions with constraints. It is possible to give explicit results for the nature of the textures. Chiral Sm-$C$ elastomers are ferro-electric. We calculate how the polarization could be mechanically reversed by large, hard or soft strains of the rubber, depending upon sample geometry.