聚合物胶束多层次自组装作用机制的同步辐射小角X射线散射研究

Hierarchical self-assembly is the most efficient route widely adopted by the living systems for system construction and physiological activities, which is also highly important for the new developments of medicine systems, functional materials, and nano-devices. Polymer micelles possess flexible structures, morphologies and functions, and can interact with each other in a diverse fashion. This has provided an excellent platform for the studies on the extension of hierarchical self-assembly methods and the mechanisms of various hierarchical self-assembly processes. This project focuses on the use of synchrotron small angle x-ray scattering technologies, developed by the Shanghai Synchrotron Radiation Facility, to investigate the dynamic process of the hierarchical self-assembly of spherical, cylindrical, and toroidal polymer micelles with controlled size and corona construction. Through the fabrication of automatically controlled sample holders, uniquely designed for in situ parameter tuning and characterization, and the subsequent adjustments of the rate, equilibrium, dissociation and reversibility of the hierarchical self-assembly, this project aims at a systematic investigation on the morphology evolution of polymer micelles and their interactions during the hierarchical self-assembly. This will be followed by a further exploration of the thermodynamics and kinetics, and eventually a relative precise model for structural analysis and simulation, which would be very helpful for acquiring deeper insights into the hierarchical self-assembly systems and push it to a higher level.

多层次自组装是生命体系所采用的最为高效的组织构筑和生理运作模式，对于新型医药体系、功能材料、微纳米器件的开发具有十分重要的意义。聚合物胶束具有灵活多变的结构、形态与功能，相互作用方式丰富多样，为拓展多层次自组装方法、解析多层次自组装的调控机制提供了良好的研究平台。本项目基于一系列具有可控尺寸与壳层结构的球状、柱状、环状嵌段共聚物胶束，依托上海光源同步辐射小角X射线散射技术，系统研究溶液中聚合物胶束的多层次自组装的动力学过程。通过搭建自动化原位调控实验装置，精确调节多层次自组装的进程、平衡、解离与可逆化转变等，系统解析多层次自组装过程中聚合物胶束的形态结构演变与相互作用机制，从而探究多层次自组装的热力学规律和动力学控制机制，并建立相关分析预测理论与模型，将对深入认识和开发各类多层次自组装体系起到有力的推动作用。

嵌段共聚物能够自组装成丰富多样的胶束结构，研究聚合物胶束的形成和演变过程，以及以胶束为基元的多层次自组装过程具有重要的科学意义。本项目以两亲性嵌段共聚物为研究对象，通过溶液自组装构建了大量的聚合物胶束，如球状胶束、蠕虫状胶束、囊泡结构、碟片状胶束、碟片阵列以及穿孔的碟片状胶束。进一步地提出了溶液-界面顺序自组装方法，得到了环状胶束、同心环状胶束以及花环团簇结构，丰富了嵌段共聚物胶束结构的多样性。运用同步辐射X射线小角散射技术，研究了球形胶束在不同浓度下的堆叠结构及其堆叠结构在原位热退火过程中的相转变行为。此外，利用氢键相互作用，把基于嵌段共聚物本身的自组装拓展到有机与无机纳米粒子的杂化自组装，通过嵌段共聚物胶束与无机二氧化硅纳米粒子的共组装，制备了大量的胶体分子及一维、二维和三维的胶体结构阵列，进一步增加了纳米结构的多样性和复杂性。本项目所构建的聚合物胶束、胶体纳米粒子结构以及所发展的界面自组装方法为小角散射未来的研究提供了丰富的物质研究基础。