LIQUID-CRYSTAL POLYMER COMPOSITES - ANOMALOUS ELECTROOPTICAL CURVE

Liquid crystal-polymer composites containing a low proportion of polym er are of interest because of their low driving voltage, but they can show anomalous electro-optical curves, such as a minimum in the electr o-optical curve. We explain the existence of this minimum, by a partia l orientation of liquid crystal domains, together with the presence of mobile polymer fragments. This partial orientation is visible using a polarizing microscope, and the presence of polymer that is not linked to the main network is proved by size exclusion chromatography of the liquid crystal extracted from the composite.