Photoinduced bending and unbending behavior of liquid-crystalline gels and elastomers

Abstract

Liquid-crystalline gels and elastomers were prepared by polymerization of mixtures containing azobenzene monomers and cross linkers with azobenzene moieties. Oriented liquid-crystalline gels and elastomer films were found to undergo anisotropic bending and unbending behavior only along the rubbing direction, when exposed to alternate irradiation of unpolarized UV and visible light. In the case of polydomain liquid-crystalline elastomer films, the bending and unbending were induced exactly along the polarization direction of incident linearly polarized light. By altering the polarization direction of light, a single film could be bent repeatedly and precisely along any chosen direction.