Molecular Crystals and Liquid Crystals, Vol.662, No.1, 61-67, 2018
Liquid-crystalline elastomer photoactuator with photorearrangeable network structures
Crosslinked liquid-crystalline polymers (CLCPs) containing azobenzene moieties show reversible macroscopic deformation upon irradiation with light. The deformation of CLCPs strongly depends on alignment of mesogens. Therefore, it is desirable that the alignment of mesogens in CLCPs can be freely controlled even after crosslinking. We successfully realigned the mesogens in CLCPs with the aid of dynamic covalent bonds to accomplish this challenge. In this study, we prepared CLCP films containing dynamic covalent bonds and photoalignable azobenzene moieties. Photoalignment of the films was performed by irradiation with linearly polarized UV light at 120 degrees C. The films after photoalignment showed bending behavior along the direction in which the mesogens had been realigned by photoalignment when irradiated with unpolarized UV light. This result indicates that alignment of mesogens in the films changes before and after photoalignment even after crosslinking.