Efficient Synthesis of Asymmetric Miktoarm Star Polymers
Efficient Synthesis of Asymmetric Miktoarm Star Polymers
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DOI：
10.1021/acs.macromol.9b02380
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发表时间：
2020-01-28
期刊：
影响因子：
5.5
通讯作者：
Bates, Christopher M.
中科院分区：
文献类型：
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作者：
Levi, Adam E.;Fu, Liangbing;Bates, Christopher M.
不对称杂臂星星聚合物具有独特的材料性能，但现有的合成策略受到单体范围和产率限制的复杂反应方案的困扰。在这里，我们介绍了一种新的合成方法创造的“mu星星”，杂臂合成后，开环易位聚合终止，绕过这些传统的合成限制，通过构建嵌段-嵌段连接在一个可扩展的一锅法，涉及（1）接枝聚合的大分子单体，然后（2）原位烯炔介导的终止安装一个单一的杂臂具有卓越的效率。这种模块化的mu星星平台干净地产生AB（n）和A（BA '）（n）杂臂星星聚合物，其在A和B化学的选择中具有前所未有的通用性，如使用许多常见的聚合物结构单元所证明的。B或BA'臂的平均数（n）容易通过Grubbs催化剂的当量来控制。虽然这些材料的特点是分散性的n，从聚合的统计，他们自组装成中间相是相同的预测精确的miktoarm星。总之，μ星星技术在设计灵活性和合成简单性方面提供了显著的提高，同时保留了精确微臂星星材料的显着相位行为。
Asymmetric miktoarm star polymers produce unique material properties, yet existing synthetic strategies are beleaguered by complicated reaction schemes restricted in both the monomer scope and yield. Here, we introduce a new synthetic approach coined "mu STAR", miktoarm synthesis by termination after ring-opening metathesis polymerization, that circumvents these traditional synthetic limitations by constructing the block-block junction in a scalable one-pot process involving (1) grafting-through polymerization of a macromonomer followed by (2) in situ enyne-mediated termination to install a single mikto-arm with exceptional efficiency. This modular mu STAR platform cleanly generates AB(n) and A(BA')(n) miktoarm star polymers with unprecedented versatility in the selection of A and B chemistries as demonstrated using many common polymer building blocks. The average number of B or BA' arms (n) is easily controlled by the equivalents of Grubbs catalyst. While these materials are characterized by dispersity in n that arises from the statistics of polymerization, they self-assemble into mesophases that are identical to those predicted for precise miktoarm stars. In summary, the mu STAR technique provides a significant boost in design flexibility and synthetic simplicity while retaining the salient phase behavior of precise miktoarm star materials.