Segmented Copolymers Synthesized by Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization Using an Asymmetric Difunctional RAFT Agent and the Utilization in RAFT-Mediated Dispersion Polymerization,Macromolecules

当前位置： X-MOL 学术 › Macromolecules › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Segmented Copolymers Synthesized by Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization Using an Asymmetric Difunctional RAFT Agent and the Utilization in RAFT-Mediated Dispersion Polymerization
Macromolecules ( IF 5.1 ) Pub Date : 2021-12-21 , DOI: 10.1021/acs.macromol.1c02233
Xinyi Luo ₁ , Kunlun Zhang ₁ , Ruiming Zeng ₁ , Ying Chen ₂ , Li Zhang _{1,

2} , Jianbo Tan _{1,

2}

Affiliation

Reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization-induced self-assembly (PISA) is an in situ growth method of increasing interest for the preparation of block copolymer nano-objects with diverse morphologies at high solids contents (10–50 wt %). Recent reports have shown that structures of multifunctional macro-RAFT agents can significantly affect RAFT-mediated PISA and the formed block copolymer nano-objects, but all these multifunctional macro-RAFT agents are limited to symmetric structures. In this study, we synthesized a novel difunctional RAFT agent with an asymmetric structure and employed in RAFT solution polymerization to prepare segmented macro-RAFT agents. Size exclusion chromatography (SEC) analysis showed that the redistribution of blocks occurred during RAFT polymerization, leading to the formation of segmented copolymers with different blocks (block number up to 4). Control experiments demonstrated that this redistribution process was derived from the unique structure of the asymmetric difunctional RAFT agent rather than monomers. The obtained segmented macro-RAFT agent was then used in RAFT-mediated dispersion polymerization to prepare well-defined block copolymer nano-objects. Owing to the unique structure of segmented block copolymers, shorter micellar nucleation was observed and a certain number of trithiocarbonate groups could be introduced on the surface of block copolymer nano-objects. The trithiocarbonate groups located on the surface of block copolymer nano-objects provide a landscape for further chain extension and functionalization. As a proof-of-concept experiment, vesicles loaded with silver nanoparticles were successfully prepared by in situ reduction of AgNO₃ and employed as a catalyst to reduce methylene blue in the presence of NaBH₄. We expect that this study will not only provide important mechanistic insights into RAFT polymerization mediated by multifunctional RAFT agents but also enable the preparation of functional block copolymer nano-objects.

中文翻译：

使用不对称双官能 RAFT 剂通过可逆加成-断裂链转移 (RAFT) 聚合合成的嵌段共聚物及其在 RAFT 介导的分散聚合中的应用

可逆加成断裂链转移 (RAFT) 介导的聚合诱导自组装 (PISA) 是一种原位在高固含量（10-50 wt%）下制备具有不同形态的嵌段共聚物纳米物体的生长方法越来越受到关注。最近的报道表明，多功能大分子RAFT剂的结构可以显着影响RAFT介导的PISA和形成的嵌段共聚物纳米物体，但所有这些多功能大分子RAFT剂都局限于对称结构。在这项研究中，我们合成了一种具有不对称结构的新型双官能 RAFT 剂，并用于 RAFT 溶液聚合制备分段大分子 RAFT 剂。尺寸排阻色谱 (SEC) 分析表明，在 RAFT 聚合过程中发生了嵌段的重新分布，导致形成具有不同嵌段的嵌段共聚物（嵌段数高达 4）。对照实验表明，这种再分布过程源自不对称双官能 RAFT 试剂的独特结构，而不是单体。然后将获得的嵌段大分子RAFT剂用于RAFT介导的分散聚合以制备明确的嵌段共聚物纳米物体。由于嵌段共聚物的独特结构，可以观察到较短的胶束成核，并且可以在嵌段共聚物纳米物体表面引入一定数量的三硫代碳酸酯基团。位于嵌段共聚物纳米物体表面的三硫代碳酸酯基团为进一步的链延伸和功能化提供了景观。作为概念验证实验，通过以下方法成功制备了载有银纳米颗粒的囊泡然后将获得的嵌段大分子RAFT剂用于RAFT介导的分散聚合以制备明确的嵌段共聚物纳米物体。由于嵌段共聚物的独特结构，可以观察到较短的胶束成核，并且可以在嵌段共聚物纳米物体表面引入一定数量的三硫代碳酸酯基团。位于嵌段共聚物纳米物体表面的三硫代碳酸酯基团为进一步的链延伸和功能化提供了景观。作为概念验证实验，通过以下方法成功制备了载有银纳米颗粒的囊泡然后将获得的嵌段大分子RAFT剂用于RAFT介导的分散聚合以制备明确的嵌段共聚物纳米物体。由于嵌段共聚物的独特结构，可以观察到较短的胶束成核，并且可以在嵌段共聚物纳米物体表面引入一定数量的三硫代碳酸酯基团。位于嵌段共聚物纳米物体表面的三硫代碳酸酯基团为进一步的链延伸和功能化提供了景观。作为概念验证实验，通过以下方法成功制备了载有银纳米颗粒的囊泡观察到更短的胶束成核，并且可以在嵌段共聚物纳米物体表面引入一定数量的三硫代碳酸酯基团。位于嵌段共聚物纳米物体表面的三硫代碳酸酯基团为进一步的链延伸和功能化提供了景观。作为概念验证实验，通过以下方法成功制备了载有银纳米颗粒的囊泡观察到更短的胶束成核，并且可以在嵌段共聚物纳米物体表面引入一定数量的三硫代碳酸酯基团。位于嵌段共聚物纳米物体表面的三硫代碳酸酯基团为进一步的链延伸和功能化提供了景观。作为概念验证实验，通过以下方法成功制备了载有银纳米颗粒的囊泡原位还原AgNO ₃并用作催化剂在NaBH ₄存在下还原亚甲基蓝。我们希望这项研究不仅能为多功能 RAFT 试剂介导的 RAFT 聚合提供重要的机理见解，而且还能制备功能性嵌段共聚物纳米物体。

更新日期：2022-01-11

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南