Enhancement of electro-optical performance in nematic emulsion films

We have found new monomers which are able to give stable nematic and isotro pic emulsions with micron-sized droplets. A poor contrast ratio in optical transmittance is obtained when thin electro-optical films of nematic emulsi ons are prepared with only one monomer. Matching between a monomer matrix r efractive index and that of a liquid crystal, and a consequent improvement of the electro-optical performance of emulsion films have been obtained by mixing such monomers. The films thus prepared show opacities less than 1% i n the absence of an applied field and a transmittances increase up to 85% b y applying a 0.2 V mu m(-1) electric field at 1 kHz. The long time stabilit y, the high contrast ratio, and the low driving fields suggest that nematic emulsion films are promising systems for electro-optical applications. (C) 1999 American Institute of Physics. [S0021-8979(99)03005-4].