Light-induced deformation of photoresponsive liquid crystals on a water surface

The photoinduced deformative behavior of liquid crystals (LCs) composed of an azobenzene chromophore was demonstrated. An azobenzene derivative having a LC phase at room-temperature was used for the study to induce the macroscopic deformation of a LC at ambient temperature. Polarizing optical microscopy (POM) analysis was carried out for all compounds, which showed characteristic schlieren textures of a nematic (N) phase. A LC droplet was placed on the water surface and then irradiated UV light to induce trans-cis photoisomerization to examine the photoinduced deformation of the LC. It was found that a photochemical process accelerated expansion and condensation behavior in pure azobenzene LC materials. The photo-deformation demonstrated in the study provided an understanding of the relationship between interface phenomena and photoinduced alignment change in LC materials.