温度-pH响应嵌段共聚物的链段运动性及胶束形成与转变动力学的NMR研究

Temperature and pH responsive polymer micelles have potential applications in catalysis, medicine and clinical diagnosis. The study of polymer micelles mainly focused on the material preparation and structural characterization, but not much reserch on the mobility of responsive segments and micellar formation and conversion dynamics. The studied materials of this applied project are the structural controlled temperature and pH responsive block polymers (PNIPA-b-PDEAEMA and PNIPA-b-PDMAEMA). Combining the TEM and LLS methods, several NMR methods including relaxation, self-diffusion and high resolution magic spinning techniques are used to study the mobility of the temperature and/or pH responsive segment, the influence of tiny change of pH responsive structure unit on the stimulated response and micellar structure, and the dynamics information of micellar formation and conversion. The applied project aims at further developing the NMR methods to study the mobility of the responsive segments and the dynamics information of the micellar formation and conversion, simultaneously giving new micro-explanation and laying the theoretic support for the micellar formation and conversion of the temperature and pH responsive polymer micelles at the micromolecular level.

温度-pH双重响应聚合物胶束在催化、医药，临床诊断等方面具有重要的应用前景。目前，该类胶束的研究主要集中在材料制备和结构表征上，而对分子内部链段运动以及胶束结构形成与转化过程的微观动力学等方面的研究还很有限。本申请项目以结构可控的温度-pH双重响应嵌段共聚物（PNIPA-b-PDEAEMA 和PNIPA-b-PDMAEMA）为研究对象，利用弛豫、自扩散、高分辨魔角旋转等多种NMR技术并结合电镜、光散射等方法，研究pH敏感单体结构的微小变化对胶束结构和响应性能的影响；温敏和pH敏感链段的运动性；温敏和pH敏感链段之间的运动相关性；以及胶束结构形成与转化过程的微观动力学。在此基础上进一步发展表征聚合物胶束链段运动性和微观结构转变动力学的NMR方法，为从微观分子层面解释聚合物胶束结构形成及其变化提供新的依据，为设计更符合应用需要的聚合物胶束提供理论基础。

利用NMR，DLS，TEM方法研究了 pH和温度诱导的嵌段聚合物 （PDM-b-PNIPA和 PDE-b-PNIPA）的胶束以及胶束-囊泡自组装行为。利用核磁共振的方法研究尿素对PNIPAM和PDEA高分子温敏相变行为的影响，可以帮助我们更好地理解尿素与蛋白的作用机理。NMR方法系统的研究了PDEA在一系列水醇（甲醇、乙醇、异丙醇和正丙醇）混合溶剂的相变行为，发现不含酰胺质子的PDEA在水-丙醇混合溶剂中存在非共溶剂效应（LCST降低），而在水-甲醇/乙醇混合溶剂不存在非共溶剂效应，说明酰胺质子不是PNIPA在水醇混合溶剂中非共溶剂效应的决定因素。