Preparation and Performance Testing of Flexible PDLC Films

Abstract

A new kind of polymer dispersed liquid crystal (PDLC) films based on nematic liquid crystal E7 and pre-polymeric composition epoxy resin E51 were prepared by polymerization induced phase separation via heating curing in this paper. The electro-optical properties of PDLC films were affected by many processing factors, for example, the weight ratio of the pre-polymer and liquid crystal, the curing temperature, curing time and film thickness. The electro-optical properties of PDLCs fabricated under different conditions were tested. The performance parameters such as contrast ratio, threshold voltage and the saturation voltage were calculated. In our case, the optimal preparation condition was 65% liquid crystal content with a curing time of 6 hours at 65oC. The PDLC film prepared in this paper showed a threshold voltage of 14.11V and a saturation voltage of 49.47V. The effect of film thickness on the electro-optical properties of PDLCs had been analyzed as well. The threshold voltage and saturation voltage of PDLC increase as the film thickness increases as so as the contrast ratio.