State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
Macromol Rapid Commun. 2023 Jan;44(2):e2200570. doi: 10.1002/marc.202200570. Epub 2022 Sep 26.
Fluorinated copolymers can self-assemble in solution and form micelles with rare properties due to the peculiar behavior of fluorinated groups. However, the process description of the self-assembly is still largely phenomenological and difficult to explain due to the tendency of the fluorinated segments to segregate from both the hydrophilic and lipophilic segments, which can result in various morphologies. Herein, the controlled formation of ellipsoidal micelles, disklike micelles, and sheets by hierarchical self-assembly of triphilic main-chain-type semifluorinated alternating graft copolymers (AB) A-g-mOEG is presented (where A represents unit of α,ω-diiodoperfluoroalkane, B represents the unit of α,ω-unconjugated diene, and mOEG represents methoxy oligo(ethylene glycol)), which are synthesized by step transfer-addition and radical-termination (START) polymerization and azide-alkyne click chemistry. Furthermore, the possible self-assembly mechanism of these micron-level aggregates is proposed, which is ascribed to the hierarchical self-assembly, crowding effect of hydrophilic chains and the interfacial tension between the fluoroalkane and alkane segments. This study can provide a facile and highly efficient approach to the synthesis of main-chain-type fluorinated graft copolymers and expand the research field for the solution self-assembly of fluorinated copolymers.
含氟共聚物可以在溶液中自组装，并由于含氟基团的特殊行为而形成具有罕见性质的胶束。然而，由于氟代链段有从亲水性和疏水性链段中分离的趋势，因此自组装的过程描述仍然在很大程度上是唯象的，难以解释，这可能导致各种形态的形成。本文通过三亲主链型半氟化交替接枝共聚物（AB）A-g-mOEG 的分级自组装，展示了椭球胶束、圆盘胶束和片状结构的可控形成（其中 A 代表α，ω-二碘全氟烷烃单元，B 代表α，ω-非共轭二烯单元，mOEG 代表甲氧基聚（乙二醇）），该共聚物是通过逐步转移加成和自由基终止（START）聚合以及叠氮-炔点击化学合成的。此外，还提出了这些微米级聚集体的可能自组装机制，归因于分级自组装、亲水链的拥挤效应以及氟烷烃和烷烃段之间的界面张力。本研究为合成主链型含氟接枝共聚物提供了一种简便、高效的方法，并扩展了含氟共聚物在溶液中自组装的研究领域。
