THERMOTROPIC LIQUID-CRYSTALS EMBEDDED IN A HIGH WATER GEL SYSTEM

An emulsion was formed when the thermotropic liquid crystal (LC) mixtu re E5 was added to an aqueous polyvinylalcohol (pva) solution and shak en. This emulsion was gelled by addition of an aqueous borax solution. The pva polymer functioned not only as the gelling agent but also app eared to act as a polymeric surfactant which stabilised the LC droplet s. This high water gel-liquid crystal (HWG-LC) system contained nearly 80 wt % water and more LC wt % than polymer. The system was thermally reversible, undergoing a gel to sol transition upon heating to 70-deg rees-C and reforming a gel upon cooling. The HWG-LC showed electroopti cal behaviour dependent upon a switched electric field when constraine d between transparent electrodes. The pressure required to form a thin film between these electrodes induced a structural emulsion in the di spersion causing LC droplet disruption and the formation of an LC netw ork in the gel.