Remolding of Main-Chain Type Crosslinked Azobenzene Liquid-Crystalline Polymers Utilizing Exchange of Covalent Bonds and Photoinduced Bending Behavior of the Remolded Films

Abstract

Crosslinked azobenzene liquid-crystalline polymers (CLCPs) show macroscopic deformation along the alignment of mesogens upon irradiation with light. Taking advantage of remote controllability and energy conversion, CLCPs are expected to be used as parts of soft robots. However, remolding is a common challenge in CLCPs due to their insolubility and infusibility. In this work, we prepared CLCPs with exchangeable covalent bonds in a main chain to remold them. When the CLCP films were stretched uniaxially under heating, mesogens were realigned along the stretching direction. Alignment of mesogens may be fixed by exchange of covalent bonds. Moreover, the remolded monodomain films show reversible bending behavior upon exposure to UV and Visible light.