Phase Transitions In Liquid Crystal Droplets

Basic studies of a liquid crystal confined to a small droplet have been motivated by the use of polymer dispersed liquid crystals' for a new generation of light shutters and displays.2 The structure of such a droplet is characterized by a specific director configuration and the spatial dependence of the orientational order parameter. Depending on temperature, droplet size, surface interaction, type of liquid crystal and external field, the phase of the material enclosed in the droplet can be either the isotropic (paranematic), nematic or boundary layer nematic phase.3 Director configurations in droplets have been studied extensi% ely,4-7 but the spatial dependence of the order parameter has been treated only for the case of a liquid crystal in contact with a solid planar surface.3.8-10 Lsing the Landaude Gennes approach," the order parameter profile was evaluated, showing how the orientational order varies with distance from the planar surface. In addition, for some values of the surface-liquid crystal coupling, the existence of the boundary layer nematic phase was predicted in a narrow tem-perature range between the isotropic (paranematic) and nematic phases.3