Abstract
Control over the operating voltage of nematic droplet/polymer films continues to be an important area of development in this class of devices. Our recent work in this area has included both materials modifications in order to alter the reorientation voltages of these films, as well as efforts to tie theory to experimental results. Here, we present evidence which shows that the shape of nematic droplets in these films is important in determining the operating voltage of a film. Specifically, we show two film systems in which the nematic droplets adopt the shape of oblate spheroids, but differ in the amount of eccentricity of the droplets. The more distorted droplets require higher reorientation fields, consistent with the model of the volume elastic deformation free energy as a major factor affecting the reorientation fields of these films. We also demonstrate that the apparent operating voltage of a film depends on which property of the film is being measured. Measurements based on film scattering, dichroism, and capacitance are presented, and the implications of these measurements with regards to apparent film operating voltages discussed.