EVIDENCE OF FLEXOELECTRICITY IN POLYMER DISPERSED LIQUID CRYSTALS

摘要

Linear electro-optical response of polymer dispersed liquid crystals (PDLC) films has been studied. By the method of photopolymerization induced phase separation (SIPS) droplets of cyanobiphenyls (E7) were formed in NOA65 photopolymer. Samples with various average nematic droplet size were systematically investigated. Temperature dependence of first harmonic electro-optic spectra was obtained. Peculiar bumps and double bumps in the phase spectra were found at temperatures close to the clearing point. Samples with narrow distribution of droplet size were characterized by a double peak of amplitude spectra in the low frequency range. Flexoelectric origin of the 1st harmonic spectra has been discussed.