摘要
采用原子转移自由基聚合(ATRP)方法合成了分子量分布较窄的嵌段型两性聚电解质聚(二甲胺基甲基丙烯酸乙酯)-嵌-聚丙烯酸(PDMA-b-PAA),并研究了其水溶液对pH、温度及小分子盐的响应行为。研究表明,PDMA-b-PAA水溶液具有pH、温度双重敏感和反聚电解质效应。其等电点在6.9左右,与理论值(7.3)非常接近;溶液在pH为5.4～7.3之间出现混浊,发生相分离;该聚电解质具有良好的可逆温敏特性,其最低临界溶液温度(LCST)为37.8℃,该温度使其可望成为用于人体的优良药物载体。
Diblock copolymer poly[（N,N-dimethylamino）ethyl methacrylate]-block-poly（acrylic acid）（PDMA-b-PAA） with a low polydispersity（PDI=1.23） has been synthesized by atom transfer radical polymerization（ATRP）.The zwitterionic properties of PDMA-b-PAA solutions and the effect of ionic strength of small molecule salt on the solution behavior have been investigated.It is shown that PDMA-b-PAA has both pH-and temperature-responsive assembly behavior with the IEP of 6.9 and the LCST of 37.8 ℃ and has anti-polyelectrolyte effect.Phase separation happened in the pH range of 5.4-7.3 and the perfect reversible thermal-responsive behaviors were clearly observed.
基金
国家自然科学基金资助项目(20806022
20736002)
高等学校博士学科点专项科研基金资助项目(200802510008)
关键词
原子转移自由基聚合
嵌段型两性聚电解质
环境敏感
反聚电解质效应
atom transfer radical polymerization（ATRP）
zwitterionic diblock polyampholyte
stimuli-response behavior
anti-polyelectrolyte effect
