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利用核磁共振方法研究了AB型双嵌段共聚物(MPEG45-b-PA32)在选择性溶剂中的自组装行为及胶束化过程.嵌段共聚物在三氟乙酸中聚氨基酸和聚乙二醇链段均处于自由运动状态,聚丙氨酸链段为无规线团结构.在向该溶液中逐渐加入氘代水的过程中,聚丙氨酸链段又重新聚集形成规整的二级结构.结合1H-NMR和COSY谱分析,结果显示这一自组装过程伴随着聚(L-丙氨酸)链段由无规线团向α-螺旋结构的构象转变,同时嵌段共聚物逐渐形成核-壳型胶束结构.利用透射电镜观察了所形成胶束的形态,嵌段共聚物主要形成粒径150 nm到220 nm的球形胶束.
The self-assembly behavior and micellarization of AB diblock copolymer (MPEG45-b-PA32) in selective solvent were studied by using nuclear magnetic resonance (NMR) In the course of gradual addition of deuterated water to the solution, the polylalanine segments re-aggregate to form a regular secondary structure. The results of 1H-NMR and COZY spectra showed that this self-assembly process was accompanied by the conformational transition of the poly (L-alanine) segment from the random coil to the α-helical structure, and the block copolymer gradually formed nuclei Shell micellar structure.The morphologies of the micelles formed were observed by transmission electron microscopy. The block copolymers mainly formed spherical micelles with particle sizes of 150 nm to 220 nm.