To prepare molecular bottlebrushes with high yield via a grafting-from strategy using a reversible deactivation radical polymerization (RDRP) technique has always been a big challenge due to the intra- and intermolecular radical–radical coupling. Herein, a polymerization-induced self-assembly (PISA)-assisted grafting-from strategy based on reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization was developed to synthesize the Janus molecular bottlebrushes with a well-defined structure and high yield using polynorbornene-g-(poly(ethylene glycols)-branch-RAFT agent) (PNB-g-(PEG-branch-CTA)) as a solvophilic multifunctional macro-CTA. The results indicated the biradical coupling terminations of propagating side chains could be significantly suppressed due to the nanoconfinement effect in the PISA of the generated Janus molecular bottlebrushes. Janus molecular bottlebrushes with a narrow molecular weight distribution (M_w/M_n < 1.25) and negligible intermolecular cross-linking at monomer conversion as high as 84% were prepared, demonstrating the efficiency and versatility of the PISA-assisted grafting-from approach.

中文翻译：

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通过 PISA-Assisted Grafting-from 策略高产合成分子瓶刷

由于分子内和分子间自由基-自由基偶联，使用可逆失活自由基聚合（RDRP）技术通过接枝策略制备高产率的分子瓶刷一直是一个巨大的挑战。在此，开发了一种基于可逆加成-断裂链转移（RAFT）分散聚合的聚合诱导自组装（PISA）辅助接枝策略，以使用聚降冰片烯合成具有明确结构和高产率的 Janus 分子瓶刷。 -g- (聚(乙二醇)-支链-RAFT剂)(PNB -g- ( PEG-支链-CTA)) 作为亲溶剂的多功能大分子 CTA。结果表明，由于生成的 Janus 分子刷的 PISA 中的纳米限制效应，可以显着抑制传播侧链的双自由基偶联终止。制备了分子量分布窄 ( M _w / M _n < 1.25) 且在单体转化率高达 84% 时分子间交联可忽略不计的 Janus 分子刷，证明了 PISA 辅助接枝方法的效率和多功能性。