Jiang Hao, Yan Tong, Cheng Meng, Zhao Zhihao, He Tinglei, Wang Zhikun, Li Chunling, Sun Shuangqing, Hu Songqing
School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Institute of Advanced Materials, China University of Petroleum (East China), Qingdao 266580, China.
Mater Horiz. 2025 Jan 20;12(2):599-607. doi: 10.1039/d4mh01129e.
Self-healing materials show exceptional application potential for their high stability and longevity. However, a great challenge of the application of self-healing materials is the tradeoff between mechanical robustness and room temperature self-healing. In order to address this tradeoff, inspired by the characteristic that small molecules of living organisms self-assemble into large protein molecules by non-covalent interactions, we constructed polyurethane with highly dynamic and strong hard domains composed of dense hydrogen bonds and π-π interactions between the phenylurea groups at the end of the side chain. The prepared elastomer (PU-HU-60) exhibits exceptional tensile performance (tensile strength is 18.27 MPa and ultimate elongation is 904.6%) and crack tolerance (fracture energy is 57.78 kJ m), surpassing those of most room temperature self-healing materials. After being damaged, the dynamic change process of hydrogen bonds and π-π interactions enables the elastomer to show a high self-healing efficiency of 92.15% at room temperature. Using molecular dynamics (MD) simulations and experiments, we verified that hydrogen bonds and π-π interactions promote the formation of hard domains and the autonomous self-healing of elastomers. The prepared elastomers can also be recycled and they showed ultra-high and restorable adhesion between metals. This work demonstrates a new strategy to balance the mechanical and self-healing properties of elastomers to expand their practical applications such as metal adhesives.
自愈材料因其高稳定性和长寿命而展现出卓越的应用潜力。然而，自愈材料应用面临的一个巨大挑战是机械强度与室温自愈能力之间的权衡。为了解决这一权衡问题，受生物小分子通过非共价相互作用自组装成大蛋白质分子这一特性的启发，我们构建了一种聚氨酯，其具有由侧链末端苯基脲基团之间密集的氢键和π-π相互作用组成的高度动态且强大的硬段。所制备的弹性体（PU-HU-60）表现出优异的拉伸性能（拉伸强度为18.27 MPa，极限伸长率为904.6%）和抗裂性（断裂能为57.78 kJ m），超过了大多数室温自愈材料。受损后，氢键和π-π相互作用的动态变化过程使弹性体在室温下展现出92.15%的高自愈效率。通过分子动力学（MD）模拟和实验，我们验证了氢键和π-π相互作用促进了硬段的形成以及弹性体的自主自愈。所制备的弹性体还可回收利用，并且在金属之间表现出超高且可恢复的粘附力。这项工作展示了一种平衡弹性体机械性能和自愈性能以拓展其实际应用（如金属粘合剂）的新策略。
