水溶性三重响应智能聚合物的合成与性能

Synthesis and Property of Water-Soluble Triply-Responsive Polymer

在CuCl/Me6TREN催化体系下,以含2-溴异丁酰基团的偶氮苯衍生物引发甲基丙烯酸-N,N-二甲氨基乙酯(DMAEMA)的原子转移自由基聚合(ATRP),得到新型水溶性三重响应智能聚合物。该聚合物可同时对光、热和pH等外部环境刺激产生响应性。利用凝胶色谱(GPC)表征聚合物的分子量及其分布。该聚合物常温下溶于水,其最低临界溶液温度(LCST)随溶液pH降低而升高。在紫外光照射下,端基偶氮苯的顺-反异构化作用使聚合物的亲水作用增强,其LCST有所提高,但在可见光照射下可恢复。该聚合物的多重刺激响应性使其在药物控制释放与智能材料领域具有潜在的应用。

A water-soluble triply-responsive intelligent homopolymer of N,N-dimethylaminoethyl methacrylate（DMAEMA） containing azobenzene group as the terminal moiety was synthesized by atom transfer radical polymerization（ATRP）.The homopolymer exhibits a thermo-induced phase transition while heated from ambient temperature to 70 ℃.The lower critical solution temperature（LCST） of the solution depends upon light,or pH value,or light/pH coactions and shows a reversible process.It is found that LCST increases as pH value decreases in the range of testing.Under the UV-light irradiation,trans-to-cis photoisomerization of azobenzene moiety resulted in a higher LCST,while it recovered under the visible light irradiation.This kind of polymers should be particularly interesting for a variety of potential applications in some promising areas such as drug controlled-releasing carriers and intelligent materials due to the multi-stimuli-responsive property.