Self-alignment and photomechanical properties of alternative multi-layered films containing azobenzene polymer liquid crystal and polyvinyl alcohol layers
Abstract We demonstrated fabrication of photo-mechanical materials alternatively-including azobenzene-side-chained acrylate polymer, PMAz6Ac, and polyvinyl alcohol, PVA, without cross-linking. The multi-bilayered (PMAz6Ac/PVA) n films were obtained by alternative spin-coating methods of PVA and PMAz6Ac solutions on glass substrates. After thermal treatment, the azobenzene groups as mesogen were self-organized and were induced out-of-plane orientation. After UV irradiation ( λ =375 nm), the self-standing films obtained by peeling off was bent to an opposite side of the light source, and the bended film reverted toward the initial position by following visible light irradiation ( λ >420 nm). Their optical properties of the PMAz6Ac layers indicated that change of molecular orientation, out-of-plane orientation and disordered random, of azobenzene groups in the PMAz6Ac layers closely related with the photo-mechanical behaviors.