Morphological and electro-optical responses of dichroic polymer dispersed liquid crystal films

Dichroic polymer dispersed liquid crystal (DPDLC) films containing different concentration of dichroic dye have been prepared by polymerization induced phase separation technique using nematic liquid crystal material in UV curable polymer NOA 65 and anthraquinone dichroic dye. The effects of applied voltage and temperature on the LC droplet morphology and its optical characteristics were studied in detail. Liquid crystal droplets containing low concentration of dye (0.25%) in polymer matrix exhibit bipolar configuration at lower applied voltage (10 V) whereas at relatively higher voltage (15 V) maltese type liquid crystal droplets were seen. In addition, low concentration DPDLC film shows better optical transmission and higher contrast ratio.