促进RAFT分散聚合诱导的高级别形貌形成的新策略

Polymerization-induced self-assembly (PISA) is a rapidly evolving method for the efficient synthesis of block copolymer nano-objects with controlled morphologies, with advantages of rapid polymerization and high solids. This proposal aims to develop new strategies to promote formation of higher-order morphologies in RAFT-mediated dispersion polymerization: 1) polymerization-induced cooperative assembly of block copolymers and homopolymers to enhance packing parameter; 2) formation of star and branched polymers to enhance packing parameter. In the former, it is key to maintain the stability of the formed homopolymers before its precipitation to ensure its cooperative assembly with the formed block copolymers. In the latter, it is important to achieve uniform self-assembly of star or branched polymers and to maintain colloidal stability. These strategies are expected to realize simultaneous polymerization control, polymer architecture design, morphology adjustment and stability maintenance. Finally, methods for simultaneous vesicle cross-linking and permeation are proposed to broaden the applications of PISA-generated higher-order morphologies.

聚合诱导自组装是近年快速发展起来的高效制备嵌段高分子纳米颗粒的方法，具有聚合速率快、固体含量高、纳米颗粒形貌可控等特点。本申请书提出在RAFT分散聚合中促进聚合诱导的高级别形貌形成的新策略：1）通过双亲性嵌段高分子与均聚高分子的协同聚合诱导组装来提高堆积参数；2）通过星型和支化型高分子的构型控制来提高堆积参数。在第一种策略中，关键解决均聚物在聚合初期的稳定性问题，使其在沉淀之前能够与聚合生成的嵌段高分子发生协同组装。在第二种策略中，关键解决非线型构型可能导致的聚合诱导自组装的均匀性及胶体稳定性问题，实现高分子构型对形貌转化的推动作用。这两种策略有望在异相聚合体系中同时实现聚合调控、构型设计、纳米颗粒形貌的控制以及胶体的稳定性。最后，申请书提出了同时实现囊泡交联与通透性控制的方法，有望推动聚合诱导自组装制备的高级别形貌的应用。

聚合诱导自组装(PISA)能够在高固体含量下可控制备不同形貌的聚合物粒子。围绕RAFT调控PISA这一研究方向，本项目研究的内容主要包括：（A）发展了嵌段共聚物与均聚物的聚合诱导协同组装（PICA）；（B）研究了聚合物的构形对PISA所制备聚合物粒子形貌的影响; （C）发展了PISA过程中不同形貌聚合物粒子的原位交联方法；（D）研究了单体的亲疏水性对PISA所形成形貌的影响；（E）研究了液晶驱动的PISA体系；（F）研究了非常规形貌，如管状与反相双连续结构粒子的形成机理。所获成果对规模化制备形貌可控的聚合物粒子具有理论指导意义。