Anchoring effect on flow-induced rotations of cholesteric droplets

Abstract

We tried to control heat-driven rotations of Ch LC droplets on a glass substrate by changing the surface anchoring with introducing azobenzene compounds as an alignment film. When irradiated by UV light, the azobenzene causes a photo-isomerization from trans to cis, which should decrease the order parameter of the adjacent LC. We investigated the rotational behavior of the Ch droplets as a function of temperature gradient (heat flow) and UV light intensity and found that the UV light not only changed the surface anchoring but also generated another torque to drive the droplets rotation.