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以丙烯酸-2-乙基己酯(EHA)、二甲基丙烯酸乙二酯(EDMA)/季戊四醇四丙烯酸酯(PETTA)为混合单体、液晶P0616A为液晶相、Irgacure 184为光引发剂,通过UV光引发制备了聚合物分散液晶(PDLCs),研究了不同烷基链长醇,即乙醇(EtOH)、正丁醇(nBA)、正己醇(nHA)、正辛醇(nOA)和正十四醇(nTA)对体系光聚合动力学及其PDLCs液晶相变温度及电光特性的影响.结果表明引入醇分子显著加快了丙烯酸酯/液晶复合体系的光聚合反应速率,提高了单体的最终转化率,其中以正丁醇体系最为明显.随着醇分子烷基链的增长,体系的转化率趋于降低,但依然明显高于不含醇的体系.醇分子的加入降低了PDLCs中液晶相的TNI,且随着醇分子烷基链长的增长,PDLCs液晶相的TNI总体上呈降低的趋势.醇分子的加入增加了PDLCs液晶微区中向列相液晶的含量,而含正丁醇和正十四醇的体系液晶微区中向列相液晶低于其它3个含醇体系.醇分子的加入明显降低了PDLCs的阈值电压和饱和电压以及对比度.结合体系的光聚合速率和单体转化率,正丁醇是改善PDLCs性能的最佳选择.
Ethylhexyl acrylate (EHA), ethylene glycol dimethacrylate (EDMA) / pentaerythritol tetraacrylate (PETTA) were used as the monomer mixture. Liquid crystal P0616A was a liquid crystal phase and Irgacure 184 was a photoinitiator. UV photoinitiated polymer dispersed liquid crystals (PDLCs) were prepared. The effects of different alkyl chain alcohols, namely ethanol (EtOH), n-butanol (nBA), n-hexanol (nHA), n-octanol (NTA) on the photopolymerization kinetics and phase transition temperature and electro-optical properties of PDLCs were investigated.The results showed that the introduction of alcohol molecules significantly accelerated the photopolymerization reaction rate of acrylate / liquid crystal composite system and increased the final conversion of monomer But the n-butanol system was the most obvious.With the increase of the alkyl chain of alcohol molecules, the conversion rate of the system tended to decrease, but it was still significantly higher than that of the alcohol-free system.The addition of alcohol molecules reduced the liquid crystal phase Of TNI, and with the increase of the alkyl chain length of the alcohol molecules, the TNI of the liquid crystal phase of PDLCs tends to decrease as a whole. The addition of alcohol molecules increases the content of nematic liquid crystal in the liquid crystal micro-domains of PDLCs, N-tetradecyl liquid crystal microdomains nematic liquid crystal less than the other three Higher alcohols added alcohol molecule significantly reduced threshold voltage and saturation voltage PDLCs, and contrast. Binding photopolymerizable monomer conversion rate and the system, is the best choice butanol PDLCs improved performance.