PREPARATION OF POLYMER DISPERSED LIQUID CRYSTAL FILMS WITH MULTI-FUNCTIONAL INIFERTER AND ITS CONTENT EFFECT ON ELECTRO-OPTICAL PROPERTIES
多官能Iniferter制备聚合物分散液晶膜及其含量对电光性能的影响

Polymer dispersed liquid crystal (PDLC) films were prepared by photopolymerization induced phase separation (PIPS) with living macromolecule,synthesized by RAFT and iniferter in sequential steps.The living macromolecule with multi-iniferter was called RAFT-MI.The effects of RAFT-MI concentration on morphologies,transmittance,threshold voltage (Vth),saturated voltage (Vsat),contrast ratio and memory effect of PDLC were studied in detail.It was found that the liquid crystal droplet of PDLC increased at first and then decreased with the concentration of RAFT-MI varying from 10 wt% to 30 wt%,while Vth decreased from 3.1 V to 1.5 V and Vsat decreased from 16 V to 6.8 V.On-state transmittance increased with the concentration of RAFT-MI varying from 10 wt% to 15 wt%,and then decreased gradually due to the mismatch between the refractive index of liquid crystal and that of polymer matrix.In addition,contrast ratio increased from 2.2 to 4.0 at first and then decreased later; memory effect of PDLC was weakened.Therefore,the new combined method of living radical polymerization RAFT and Iniferter successfully improved the electro-optical properties of PDLC.