Toward Sulfur-Free RAFT Polymerization Induced Self-Assembly
Toward Sulfur-Free RAFT Polymerization Induced Self-Assembly
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DOI：
10.1021/acsmacrolett.7b00857
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发表时间：
2017-12-01
影响因子：
7.015
通讯作者：
Bon, Stefan A. F.
中科院分区：
文献类型：
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作者：
Lotierzo, Andrea;Schofield, Ryan M.;Bon, Stefan A. F.
聚合诱导自组装（比萨）使用基于甲基丙烯酸酯的大分子单体作为RAFT试剂是一个未开发的，有吸引力的路线，使自组装胶体物体。然而，由于其固有的低反应性，这类RAFT试剂在非均相聚合中的使用并非微不足道。在这项工作中，我们证明了两个障碍需要克服，一个是控制链增长（传播），其他单体分配。甲基丙烯酸羟丙酯在聚（甲基丙烯酸甘油酯）大分子单体存在下在水中的间歇分散聚合显示出有限的控制链增长。半连续实验，其中单体进料改善的结果只有在一定程度上。控制传播是必不可少的比萨，以允许动态重排的胶体结构。我们解决了单体分配（由不受控制的颗粒成核引起）的问题，通过用已经从溶液中“相分离”的两亲性温敏二嵌段共聚物开始聚合。TEM分析表明，比萨是成功的，并在整个聚合得到不同的粒子形态。
Polymerization induced self-assembly (PISA) using methacrylate-based macromonomers as RAFT agents is an unexplored, attractive route to make self-assembled colloidal objects. The use of this class of RAFT-agents in heterogeneous polymerizations is however not trivial, because of their inherent low reactivity. In this work we demonstrate that two obstacles need to be overcome, one being control of chain-growth (propagation), the other monomer partitioning. Batch dispersion polymerizations of hydroxypropyl methacrylate in the presence of poly(glycerol methacrylate) macromonomers in water showed limited control of chain-growth. Semicontinuous experiments whereby monomer was fed improved results only to some extent. Control of propagation is essential for PISA to allow for dynamic rearrangement of colloidal structures. We tackled the problem of monomer partitioning (caused by uncontrolled particle nucleation) by starting the polymerization with an amphiphilic thermoresponsive diblock copolymer, already "phase-separated" from solution. TEM analysis showed that PISA was successful and that different particle morphologies were obtained throughout the polymerization.