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基于可逆加成裂解链转移自由基(RAFT)聚合法开发了一系列新型双亲水嵌段共聚物——聚甲基丙烯酸-b-聚N-(2-甲基丙烯酰氧乙基)吡咯烷酮(PMAA-b-PNMP),并利用凝胶渗透色谱法(GPC)和~1H NMR对其结构进行了表征。光散射和冷冻电镜的结果表明,此类双亲水嵌段共聚物的水溶液具有pH和温度诱导胶束化的现象,而且PNMP的聚合度对胶束化的pH和温度影响都非常大。一般而言,PNMP的聚合度越大,胶束化的pH值越小,胶束化的温度则越高。pD相关的~1H NMR结果表明,PNMP与PMAA片段和水分子之间氢键的削弱以及PNMP与PMAA链之间相互作用的增强是pH诱导PMAA-b-PNMP胶束形成的主要原因,而PNMP片段与水分子之间氢键的削弱则是温度诱导PMAA-b-PNMP胶束形成的主要原因。此外,我们发现在PMAA-b-PNMP体系中制备的纳米金颗粒的大小可通过溶液pH进行可控调节。总体而言,pH值越高,金纳米颗粒的粒径越小。
A series of novel amphiphilic block copolymers - poly (methacrylic acid) -b-poly (N- (2-methacryloyloxyethyl) pyrrolidone PMAA-b-PNMP). Its structure was characterized by gel permeation chromatography (GPC) and 1H NMR. The results of light scattering and cryoelectron microscopy showed that the aqueous solution of the amphiphilic block copolymer had pH and temperature induced micelle formation, and the degree of polymerization of PNMP had a great effect on the pH and temperature of micellarization. In general, the greater the degree of polymerization of PNMP, the smaller the pH of the micellarization, the higher the temperature of the micellarization. The ~ 1H NMR results of pD showed that the weakening of hydrogen bonds between PNMP and PMAA fragments and water molecules and the enhancement of the interaction between PNMP and PMAA chains were the main reasons for the pH-induced PMAA-b-PNMP micelles formation. PNMP The weakening of the hydrogen bond between the fragment and the water molecule is the main reason for the temperature-induced formation of PMAA-b-PNMP micelles. In addition, we found that the size of gold nanoparticles prepared in PMAA-b-PNMP system can be controlled by solution pH. Overall, the higher the pH, the smaller the particle size of the gold nanoparticles.