Polymer dispersed liquid crystals for large area switchable windows: Effect of liquid crystal loading

Polymer dispersed liquid crystals are composite materials which have been p roposed in the last years as large area electrically switchable windows. Th eir electro-optical performance is strictly related to the morphology of li quid crystal droplets. We have investigated the morphological and electro-o ptical properties of droplets of nematic liquid crystals dispersed in NOA65 polymer matrix. We found that droplets size and dispersion become larger a nd larger as the liquid crystal loading is increased. At higher concentrati ons of liquid crystal two different distribution of droplet size are recogn ised. Switching fields and haze in the ON state show a minimum value when t he liquid polymer/crystal weight ratio is around 55:45 for which the best p erformance is achieved.