Miwa Yohei, Udagawa Taro, Kutsumizu Shoichi
Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu, 501-1193, Japan.
PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan.
Sci Rep. 2022 Jul 25;12(1):12009. doi: 10.1038/s41598-022-16156-9.
Dynamic crosslinking of flexible polymer chains via attractive and reversible interactions is widely employed to obtain autonomously self-healable elastomers. However, this design leads to a trade-off relationship between the strength and self-healing speed of the material, i.e., strong crosslinks provide a mechanically strong elastomer with slow self-healing property. To address this issue, we report an "inversion" concept, in which attractive poly(ethyl acrylate-random-methyl acrylate) chains are dynamically crosslinked via repulsively segregated fluoroalkyl side chains attached along the main chain. The resulting elastomer self-heals rapidly (> 90% within 15 min) via weak but abundant van der Waals interactions among matrix polymers, while the dynamic crosslinking provides high fracture stress (≈2 MPa) and good toughness (≈17 MJ m). The elastomer has a nonsticky surface and selectively self-heals only at the damaged faces due to the surface segregation of the fluoroalkyl chains. Moreover, our elastomer strongly adheres to polytetrafluoroethylene plates (≈60 N cm) via hot pressing.
通过有吸引力且可逆的相互作用对柔性聚合物链进行动态交联，被广泛用于制备具有自主自修复性能的弹性体。然而，这种设计导致材料的强度和自修复速度之间存在权衡关系，即强交联会提供一种机械强度高但自修复性能缓慢的弹性体。为了解决这个问题，我们提出了一种“反转”概念，其中具有吸引力的聚（丙烯酸乙酯-无规-甲基丙烯酸甲酯）链通过沿主链连接的排斥性分离氟代烷基侧链进行动态交联。所得弹性体通过基体聚合物之间微弱但丰富的范德华相互作用快速自修复（15分钟内>90%），而动态交联提供了高断裂应力（约2MPa）和良好的韧性（约17MJ m）。由于氟代烷基链的表面偏析，该弹性体具有不粘表面，并且仅在受损表面选择性地自修复。此外，我们的弹性体通过热压与聚四氟乙烯板牢固粘附（约60N cm）。
