Department of Polymer Engineering, Pukyong National University, Busan, 48513, Republic of Korea.
Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44429, Republic of Korea.
Nat Commun. 2021 Jan 27;12(1):621. doi: 10.1038/s41467-021-20931-z.
Self-repairable materials strive to emulate curable and resilient biological tissue; however, their performance is currently insufficient for commercialization purposes because mending and toughening are mutually exclusive. Herein, we report a carbonate-type thermoplastic polyurethane elastomer that self-heals at 35 °C and exhibits a tensile strength of 43 MPa; this elastomer is as strong as the soles used in footwear. Distinctively, it has abundant carbonyl groups in soft-segments and is fully amorphous with negligible phase separation due to poor hard-segment stacking. It operates in dual mechano-responsive mode through a reversible disorder-to-order transition of its hydrogen-bonding array; it heals when static and toughens when dynamic. In static mode, non-crystalline hard segments promote the dynamic exchange of disordered carbonyl hydrogen-bonds for self-healing. The amorphous phase forms stiff crystals when stretched through a transition that orders inter-chain hydrogen bonding. The phase and strain fully return to the pre-stressed state after release to repeat the healing process.
自修复材料努力模仿可修复和有弹性的生物组织；然而，由于修复和增韧是相互排斥的，它们的性能目前还不足以商业化。在此，我们报告了一种碳酸盐型热塑性聚氨酯弹性体，它可以在 35°C 下自修复，并且具有 43 MPa 的拉伸强度；这种弹性体与鞋类鞋底一样坚固。值得注意的是，由于硬段堆积不良，其软段中含有丰富的羰基，且完全非晶，相分离可忽略不计。它通过氢键阵列的可逆无序到有序转变以双机械响应模式工作；它在静态时修复，在动态时增韧。在静态模式下，非晶硬段通过无序羰基氢键的动态交换促进自修复。当通过有序链间氢键的转变拉伸时，非晶相形成硬的晶体。在释放后，相和应变完全恢复到预应力状态，从而重复修复过程。
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