Healable and recyclable poly(urethane-urea) elastomers with high mechanical strength, extreme toughness, and excellent crack tolerance via a supramolecular self-assembly strategy for strain sensor application

Conductive materials with high strength, high toughness and excellent crack resistance are important components of high-performance wearable electronic devices. Wearable strain sensors require robust materials to ensure durability and stability, as well as a wide strain range, to expand their applications. In this work, inspired by the unique dense hydrogen bond arrays in spider silk, a multifunctional supramolecular poly(urethane-urea) (SiPUU-IPDA) elastomers integrating high mechanical strength, toughness and excellent crack resistance have been successfully synthesized. Relying on high-density hydrogen bond arrays, the SiPUU-IPDA elastomers exhibited a high mechanical strength of 71.2 MPa, a toughness of 734.3 MJ/m³ and a fracture energy of up to 124.1 kJ/m². Owing to the dynamic reversibility of the hydrogen bonds arrays, the SiPUU-IPDA elastomers exhibited excellent healability and recyclability. Moreover, a crack tolerance, recyclability and strain sensor composite (SiPUU-IPDA₂/TA/CNTs) is prepared using the SiPUU-IPDA₂ elastomer as the matrix. These SiPUU-IPDA elastomers offer great potential for the design and preparation of robust materials with healability and recyclability for various applications that require high strength and toughness.