Preparation And Photoelectric Properties Of Polymer Dispersed Liquid Crystal Films

Polymer dispersed liquid crystal (PDLC) is a liquid crystal droplets dispersed inthe monomer of polymer composite materials which in the electric field under theaction of the switch show two states：transparent and scattering. In the past20years，PDLC film composite material have obtained the rapid development and widelyapplication,mainly as a result of the PDLC film has a high contrast,simplepreparation， no needed Polaroid and so on， and could be used as intelligent glass，grating， display screen. Therefore， it is not only currently a good research topic inthe field of liquid crystal，but also has good potential market for the industry.First the potential market value and application fields of PDLC film werediscussed briefly, and the domestic and foreign research status of PDLC film alsowere discussed on This paper. For the preparation of the superior performance of thePDLC film， the preparation process of PDLC film must be understood. With moreand more domestic and foreign scholars paying a attention on the PDLC film，itprovides a solid theoretical foundation for application of PDLC film.There are five methods for preparation on PDLC film,such as TemperatureInduced Phase Separation， Solvent Induced Phase Separation， PolymerizationInduced Phase Separation， Micro-capsulation process，LC in templated cavities.The Polymerization Induced Phase Separation is used commonly compared with theother methods， because of artificially controlled the reaction from beginning to endand LC size uniformity.In addition，for the preparation of the superior performance of the PDLC film，it is the key to control the size of precipitation of liquid crystal. So many factors onpreparation of PDLC film should be consider，such as curing time， film thickness，pre-polymer,primer，photoinitiator and so on. In this paper， through the two system----aliphatic polyurethane acrylate and aromatic urethane acrylate， theinfluencing factors have been explored. The purpose is to prepare low， voltage，maximum transmittance on the open state,fast response time of PDLC film.Since the resin during curing process will appear the volume shrinkage， whichwill cause the PDLC film dehiscence or PDLC photoelectric properties of failure. Inorder to solve this problem，this paper synthesized the expansive monomer，and theexpansive monomer content on the photoelectric properties of PDLC films andvolume shrinkage are discussed.The formulation that the pre-polymer Photomer6210: pre-polymer CN131=2:1,BA: LMA:SMA: DMAEMA=2:1:1:1,50%of liquid crystal，10min of curingtime，5cm height of light intensity，25um of glass bead size，1%expansion monomercontent could be prepared for good PDLC film.