中文摘要：

利用原子转移自由基聚合（ATRP）技术合成了含不同端基取代基的偶氮苯三臂星形侧链液晶聚合物.均苯三酚与2-溴异丁酰溴通过酯化反应制备三官能团引发剂,引发偶氮苯单体6-[4-（4-甲氧基苯基偶氮）酚氧基]己基甲基丙烯酸酯（MMAzo）或6-[4-（4-乙氧基苯基偶氮）酚氧基]己基甲基丙烯酸酯（EMAzo）的ATRP反应.利用核磁共振氢谱（^1HNMR）、凝胶色谱（GPC）、差示扫描量热法（DSC）和偏光显微镜（POM）等手段对星形聚合物进行表征.星形聚合物的液晶性与相应均聚物相似,但偶氮苯端基取代基的不同导致星形聚合物的液晶性差别显著.在紫外/可见光照射下星形聚合物呈现明显的异构化转变.

英文摘要：

　Tri-arm star side-chain liquid crystalline（LC）polymers containing azobenzene with different terminal substituents were synthesized by atom transfer radical polymerization.Trifunctional initiator prepared by the esterification between phloroglucinol and 2-bromoisobutyryl bromide was utilized to initiate the polymerization of 6-[4-（4-methoxyphenylazo）phenoxy]hexyl methacrylate or 6-[4-（4-ethoxyphenylazo）phenoxy]hexyl methacrylate.The star polymers were characterized by ^1H NMR,gel permeation chromatography,differential scanning calorimetry,and polarizing optical microscopy.The tri-arm star side-chain LC polymer with p-methoxyazobenzene moieties exhibits a smectic and nematic phase,while that with p-ethoxyazobenzene moieties shows only a nematic phase,which derives from different terminal substituents.The star polymers have similar LC behavior to the corresponding linear homopolymers.Both star polymers show photoresponsive isomerization under the irradiation with UV-Vis light in THF solution.