Electric Field Dependent Textural Variation inside the Liquid Crystal Droplets with Homeotropic Alignment

The alignment of liquid crystal inside the droplets highly influences the electro-optical behaviour of polymer dispersed liquid crystals (PDLCs). In PDLCs with initial transparent state, LC droplets exhibit homeotropic boundary conditions with darker zone at the centre with ring shaped boundary. In the present work, the textures were observed under parallel and crossed polarizers. The captured information revealed that there are no changes in the central zone of the droplets due to the perfect homeotropic alignment of liquid crystals inside the droplet. The count of the droplets with different ranges was measured using ImageJ software. Further, the effect of electric field on textural variation inside the droplets, measuring the ratio of the size of darker zone to the size of droplet (a/d) was analysed by applying image processing. The response curve was obtained for different range of sizes of droplets from the plot of a/d ratio vs applied voltage and found supportive to the measure of the textural variation inside the LC droplets. Therefore, the a/d ratio can be the valuable parameter for optimizing the parameters such as droplet size, area of darker zone and required voltage for energy efficient PDLC devices.