大分子链转移剂活性对聚合物分散液晶电光性能的影响

采用可逆加成-断裂链转移(RAFT)、引发转移终止(Iniferter)、反向原子转移自由基聚合(RATRP)等活性自由基聚合方法,合成了分子量相近而带有不同端基的大分子链转移剂。通过紫外光聚合诱导相分离法制备聚合物分散液晶(PDLC)膜。通过研究大分子链转移剂光引发活性,发现采用RAFT聚合制备的大分子链转移剂具有较高的光活性,带有Iniferter活性基团的大分子链转移剂光活性很低。对不同大分子链转移剂制备的PDLC膜的电光性能进行比较,发现采用RAFT法合成的具有高光活性的大分子链转移剂能够使PDLC膜具有较高的开态透光率和较低的驱动电压。加入大分子链转移剂会导致PDLC记忆效应升高。

Effect of Macro Chain Transfer Agent Activity on the Electro-Optical Properties of Polymer Dispersed Liquid Crystal

Living polymerization methods such as reversible addition-fragmentation chain transfer(RAFT) polymerization,initiator-transfer-ter minator agent(iniferter) polymerization and reverse atom transfer radical polymerization(RATRP) were used to synthesize macro chain transfer agents which have similar molecular weight.Polymer dispersed liquid crystal(PDLC) films were prepared by polymer induced phase separation(PIPS).The chain transfer agent prepared by RAFT polymerization showed the highest optical activity,and the chain transfer agent prepared by Iniferter polymerization showed low optical activity.The electro-optical properties of PDLC films prepared by different macro chain transfer agents and different curing time were also discussed.It is found that the PDLC films containing chain transfer agents prepared by RAFT polymerization shows high on-state transmittance and low on-state drive voltage.The addition of macro chain transfer agent could increase the memory effect of PDLC films.