Microstrain Sensing Using Chiral-Nematic Liquid Crystal Elastomers with Auxetic Structures

Abstract

Chiral nematic liquid crystal elastomers (N* LCEs) are known for their wavelength-selective reflection based on their helical molecular orientation. The reflection wavelength can be tuned by manipulating the pitch length of the helical structure, allowing for control over the color of the N* LCEs film through mechanical deformation. Recently, we have investigated the potential of N* LCE films for visualizing stress and strain of the film. In this study, we focus on enhancing stress and strain sensing capabilities in N* LCEs using an auxetic structure, which exhibits a negative Poisson's ratio during elongation. We demonstrated that the incorporation of the auxetic structure facilitates significant change in the reflection color even with small deformation.