不同嵌段比的PEG-b-PDMAEMA共聚物在水溶液中的自聚集行为

采用氢核磁共振(¹H-NMR)、动态光散射(DLS)及透射电子显微镜(TEM)对聚乙二醇-嵌段-聚甲基丙烯酸N,N-二甲氨基乙酯(PEG-b-PDMAEMA)三种具有不同PEG/PDMAEMA嵌段比的PEG-b-PDMAEMA共聚物在水溶液中的自聚集行为进行了研究. 研究表明, 两嵌段比例是影响聚合物胶束化过程的关键因素: 只有当其中聚乙二醇含量较低(质量分数低于33%)时, 聚合物才具有其pH/温度敏感胶束化特性. 此外, 共聚物溶液随温度胶束化过程与共聚物嵌段比大小密切相关. PEG-b-PDMAEMA这种不同于传统双亲性嵌段共聚物(DHBCs)在选择性溶剂中独特的胶束化行为, 是由聚合物溶液体系中各种基团之间的氢键作用决定的.

Self-aggregation Behavior of PEG-b-PDMAEMA Copolymers with Different Block Ratios in Aqueous Solution

1H-NMR,dynamic light scattering (DLS),and transmission electron microscopy (TEM) were used to study the effect of block ratio on the self-aggregation behavior of poly(ethylene glycol)-b-N,N-dimethylamino ethyl methacrylate] (PEG-b-PDMAEMA) copolymers in water. The results revealed that the block ratio of the two blocks was the key factor to its micellization process. The PEG mass content less than 33% is the precondition for the copolymer to show its unique pH-and thermo-responsive micellization behavior. Also,the micellization process was closely related to the block ratio of the two constitutional blocks. The hydrogen bonding interaction between different groups in the polymeric system may account for it.