Meso- and microscopic motions in photoresponsive liquid crystalline polymer films.

Photoresponsive azobenzene-containing systems ranging from molecular to macroscopic material levels have greatly been increasing their significance in materials chemistry. This review focuses on the studies on light induced or triggered motions in azobenzene liquid crystalline (LC) polymer films at mesoscopic and microscopic levels. Due to the cooperative nature of liquid crystalline materials, highly efficient photoalignment and photo-triggered migrating motions are realized in mostly repeated manners. Here, recent advances in surface-grafted LC polymer brushes, LC block copolymer films, and LC polymer films that exhibit mass migrations are overviewed. Such newly emerged photoresponsive systems are expected to provide new possibilities and applications in polymer thin film technologies.