High-performance, in-plane switching liquid crystal device utilizing an optically isotropic liquid crystal blend of nanostructured liquid crystal droplets in a polymer matrix

Abstract

A light scatter-free, transparent, thermally stable, optically isotropic liquid crystal mixture was achieved among three different mixtures of liquid crystal E7: Norland Optical Adhesive 65 with concentrations 30:70, 40:60, and 50:50wt%. The 50:50wt% mixture exhibited the best performed optically isotropic state when exposed to ultraviolet light of intensity 150mW/cm2 for droplet formation. The high intensity ultraviolet light curing process induces nano-sized liquid crystal droplets in the polymer matrix of average droplet size 218nm, characterized by scanning electron microscope. The analyzed result shows an excellent contrast ratio (CR) equal to 1574 at the normal direction and a high CR at a wide viewing angle. The magnitude of Kerr constant in these nano-sized PDLC was ~7.36×10−10mV−2, which was more than ~330 times that of a conventional Kerr material such as nitrobenzene. Unprecedented fast rising and falling times of approximately 385µs and 1.1ms, respectively, were achieved for the device. This high-performance material also eliminated the long-term hurdle of hysteresis to make it a promising candidate for next-generation display and photonic technologies.