采用可逆加成-断裂链转移自由基聚合方法制备了聚丙烯酸叔丁酯-b-聚(N-异丙基丙烯酰胺)(PtBA-b-PNIAAm)嵌段共聚物,用核磁共振谱和凝胶渗透色谱对其结构和组成进行了表征。通过水解反应脱去嵌段PtBA的叔丁基得到聚丙烯酸-b-聚(N-异丙基丙烯酰胺)(PAA-b-PNIAAm)嵌段共聚物,使用核磁共振谱确定了其水解率约为85.5%。使用动态光散射和原子力显微镜技术对其在水溶液中的温度和pH敏感性自组装行为做了初步研究。结果表明,PAA-b-PNIAAm胶束的临界聚集pH值约为5.3,最低临界溶解温度(LCST)约为34.0℃。
Diblock copolymer of poly(tert-butyl acrylate)-block-poly(N-isopropylacrylamide)(PtBA-b-PNIAAm) with designed molecular weight and narrow molecular weight distribution was synthesized by sequential reversible addition-fragmentation chain transfer(RAFT) polymerization.The well-defined structure and composition of polymer were characterized by 1H-NMR and GPC.Followed by selective hydrolysis of the tert-butyl groups of poly(tert-butyl acrylate) block,poly(acrylic acid)-block-poly(N-isopropylacrylamide)(PAA-b-PNIAAm) was prepared.The degree of hydrolysis was determined to be more than 85.5% by the 1H-NMR results.The self-assembly behavior and morphology of thermo-and pH-responsive block copolymers in aqueous solution were investigated by dynamic light scattering(DLS) and atomic force microscopy(AFM).The results indicate that the critical aggregation pH value is about 5.3 and the lower critical solution temperature(LCST) is about 34.0 ℃.
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