Experimental Studies of Thermo-Induced Mechanical Effects in the Main-Chain Liquid Crystal Elastomers

Abstract

Liquid crystal elastomers (LCEs), either side-chain LCEs (SCLCEs) or main-chain LCEs (MCLCEs), possess a combination of LC and elastic properties, and are expected to be used as artificial muscles. We experimentally investigated the thermo-induced mechanical effects showed by MCLCEs with four different crosslinker concentrations, i.e., 8%, 12%, 14% and 16%. The samples were heated up to the critical temperature and the images were recorded. The samples made the contraction in direction parallel to the director and the expansion in direction perpendicular to the director. Drastic changes occured when approaching the critical temperature, the greater the crosslinkers concentration the bigger the maximum contraction and expansion. The shape anisotropy expression showed that heating up to the critical temperature caused the system no longer in anisotropic state.