Out-of-plane Strain Measurement of A Silicone Elastomer by means of A Cholesteric Liquid Crystal Sensor

Abstract

Understanding the three-dimensional deformation of soft materials is needed for development of soft robots and flexible devices. In particular, “strain” is an important indicator reflecting the deformation of materials as it could be measured accurately. Although electrical sensors have been commonly used for investigating strain, local internal strain analysis remains a challenge due to difficulty of external connections. In this work, local internal strain in polydimethylsiloxane (PDMS) induced by stretching is quantitatively measured via the selective reflection of a cholesteric liquid crystal (CLC) sensor. The results reveal that the out-of-plane strain in the stretched PDMS films occurs by approximately 17% at tensile strain of 50%. Out-of-plane strains show the same value in near-surface and center of PDMS films. Understanding of the deformation behavior of soft materials such as PDMS could accelerate the development of soft robots and flexible devices.