School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
Joint Laboratory of Advanced Biomedical Materials (NFU-UGent), Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China.
Adv Mater. 2023 Jun;35(26):e2300937. doi: 10.1002/adma.202300937. Epub 2023 May 12.
Soft self-healing materials are compelling candidates for stretchable devices because of their excellent compliance, extensibility, and self-restorability. However, most existing soft self-healing polymers suffer from crack propagation and irreversible fatigue failure due to easy breakage of their dynamic amorphous, low-energy polymer networks. Herein, inspired by distinct structure-property relationship of biological tissues, a supramolecular interfacial assembly strategy of preparing soft self-healing composites with unprecedented crack propagation resistance is proposed by structurally engineering preferentially aligned lamellar structures within a dynamic and superstretchable poly(urea-ureathane) matrix (which is elongated to 24 750× its original length). Such a design affords a world-record fracture energy (501.6 kJ m ), ultrahigh fatigue threshold (4064.1 J m ), and outstanding elastic restorability (dimensional recovery from 13 times elongation), and preserving low modulus (1.2 MPa), high stretchability (3200%), and high room-temperature self-healing efficiency (97%). Thereby, the resultant composite represents the best of its kind and even surpasses most biological tissues. The lamellar 2D transition-metal carbide/carbonitride (MXene) structure also leads to a relatively high in-plane thermal conductivity, enabling composites as stretchable thermoconductive skins applied in joints of robotics to thermal dissipation. The present work illustrates a viable approach how autonomous self-healing, crack tolerance, and fatigue resistance can be merged in future material design.
软自修复材料因其出色的顺应性、可拉伸性和自修复性而成为可拉伸器件的理想候选材料。然而，大多数现有的软自修复聚合物由于其动态无定形、低能量聚合物网络容易断裂，因此容易发生裂纹扩展和不可逆的疲劳失效。在此，受生物组织独特的结构-性能关系的启发，通过结构工程，在动态超拉伸聚（脲-氨酯）基质内优先排列层状结构，提出了一种用于制备软自修复复合材料的超分子界面组装策略，该策略具有前所未有的抗裂纹扩展能力（可拉伸至 24750 倍原长度）。这种设计提供了创世界纪录的断裂能（501.6 kJ m）、超高疲劳阈值（4064.1 J m）和出色的弹性恢复能力（从 13 倍伸长率恢复尺寸），并保持低模量（1.2 MPa）、高拉伸性（3200%）和高室温自修复效率（97%）。因此，所得复合材料是同类材料中的佼佼者，甚至超过了大多数生物组织。层状二维过渡金属碳化物/氮化物（MXene）结构还导致相对较高的面内热导率，使复合材料可用作机器人关节的可拉伸热传导皮肤，以散热。本工作说明了一种可行的方法，即如何在未来的材料设计中融合自主自修复、抗裂纹和耐疲劳性。
