State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China.
Mater Horiz. 2021 Aug 31;8(9):2553-2561. doi: 10.1039/d1mh00638j.
Biological tissues can grow stronger after damage and self-healing. However, artificial self-healing materials usually show decreased mechanical properties after repairing. Here, we develop a self-healing strengthening elastomer (SSE) by engineering kinetic stability in an ionomer. Such kinetic stability is enabled by designing large steric hindrance on the cationic groups, which prevents the structural change driven by thermodynamic instability under room temperature. However, once heat or external force is applied to disrupt the kinetic stability, the inherent thermodynamic instability induces the SSEs to form bigger and denser aggregates, thereby the material becomes stronger during the healing process. Consequently, the self-healing efficiency of fractured SSEs is as high as 143%. Unlike conventional ionomers whose mechanical properties change with time uncontrollably due to the thermodynamic instability, the SSEs show tunable self-healing strengthening behavior, thanks to the kinetic stability. This work provides a novel and universal strategy to fabricate biomimetic self-healing strengthening materials.
生物组织在受到损伤后可以自我修复并变得更强。然而，人工自修复材料在修复后通常会表现出机械性能的下降。在这里，我们通过在离聚物中设计动力学稳定性来开发一种自修复增强弹性体（SSE）。这种动力学稳定性是通过在阳离子上设计大的空间位阻来实现的，这可以防止在室温下由热力学不稳定性驱动的结构变化。然而，一旦热量或外力施加到破坏动力学稳定性，固有的热力学不稳定性会促使 SSE 形成更大、更密集的聚集体，从而在修复过程中使材料变得更强。因此，断裂的 SSE 的自修复效率高达 143%。与传统的离聚物不同，由于热力学不稳定性，其机械性能会随着时间的推移而不可控地发生变化，SSE 由于动力学稳定性而表现出可调的自修复增强行为。这项工作为制造仿生自修复增强材料提供了一种新颖且通用的策略。
