Effects of perfluoration of epoxy-amine polymer matrices on the electro-optical performance of polymer dispersed liquid crystal films

Polymer dispersed liquid crystal (PDLC) films were obtained by combined thermally and polymerization induced phase separation processes initiated by the temperature controlled polycondensation reaction of monomers carrying either epoxy or amine groups. The epoxy diglycidyl ether of bisphenol A (DGEBA) and two different amines very used: an aliphatic amine and an aromatic fluorinated amine. The nematic liquid crystal mixture E7 was employed. The electro-optical performance of the obtained PDLC films was analyzed as a function of reaction cure in the absence and presence of the fluorinated amine. It was found that the addition of the fluorinated amine has a strong influence on the transmission vs voltage curves. A remarkable decrease of threshold- and saturation voltages as well as an increase of the transmission values in the on-state was observed.