Effect of polymer-dispersed liquid crystal morphology on its optical performance

The effect of the preparation method and its parameters and system composition on the polymer-dispersed liquid crystal morphology are described including size, shape, and concentration of liquid crystal droplets. Three different methods of polymer-dispersed liquid crystal preparation – encapsulation, solvent-induced phase separation, and photopolymerization- induced phase separation have been studied. It has been confirmed that the mean size of liquid crystal droplets is proportional to the liquid crystal concentration and approximately inversely proportional to the solidification rate. Depending on the preparation parameters it is possible to obtain, from the same components, a composite in which liquid crystal droplets’ size differs by four orders of magnitude. The driving voltage decreases while switching time increases with a size of liquid crystal droplets. The composites containing elongated liquid crystal droplets exhibit different electrooptical properties than those containing spherical droplets. Generally, changing composite morphology one can adjust electrooptical performance of polymer-dispersed liquid crystal.