Electro-optic Studies on Polymer-Dispersed Liquid Crystal Composite Films.I.Composites of PVB-E7

摘要

The eletro-optic performance characteristic of polymer-dispersed liquid crystal 9PDLC) composite films out of poly(vinyl butyral) (PVB) and nematic liquid crystal (E7) have been studied for a wide range of PVB-E7 composite compositions (20-70 wt % of E7).Composites were prepared by solvent casting from chloroform at room temperature.A scanning electron microscopystudy showed that a E7 phase is continuously embedded in chink-like structure of PVB matrix.Optical transmittance of the composite films (of 60 and 70 wt % loading of E7) under an alternating current (ac) electric field (0-250,V_(p-p)) and frequency (50 Hz to 1 KHz) were measured employing He-Ne laser (#lambda# = 632.8 nm).The results indicate that the (PVB-E7) composite exhibits a.memory effect.In the memory state,higher transmittance is preserved without applying voltage.The memory state can be erased and changed to the scattering Off-state by heating the film to the clearing temperature of the liquid crystal.