Piezoelectricity of Cholesteric Elastomers

TL;DR

This paper theoretically investigates the piezoelectric properties of cholesteric elastomers, revealing that only shear strains or local rotations induce polarization, contrary to previous assumptions about compression or elongation effects.

Contribution

It provides a symmetry-based theoretical analysis of piezoelectricity in cholesteric elastomers, highlighting the specific strains that generate polarization and proposing molecular mechanisms.

Findings

Compression or elongation along the pitch axis does not produce piezoelectric response.

Shear strains or local rotations induce polarization.

Theoretical symmetry considerations align with fundamental principles.

Abstract

We consider theoretically the properties of piezoelectricity in cholesteric elastomers. We deduce using symmetry considerations the piezoelectric contributions to the free energy in the context of a coarse-grained description of the material. In contrast to previous work we find that compressions or elongations of the material along the pitch axis do not produce a piezoelectric response, in agreement with fundamental symmetry considerations. Rather only suitable shear strains or local rotations produce a polarization. We propose some molecular mechanisms to explain these effects.