Recent progress in intrinsic self-healing polyurethane elastomer materials

Self-healing materials can detect damage and repair it through intrinsic mechanisms, addressing critical issues such as performance degradation and shortened service life of polymer materials during operation. They represent a pivotal research direction in the field of polymer science. Self-healing technologies are broadly classified into two categories: extrinsic and intrinsic. Extrinsic self-healing relies on a synergistic carrier-healing agent-catalyst system. Although the healing process is straightforward, it suffers from inherent limitations including high raw material costs, complex fabrication processes, and limited healing cycles at the same damage site. In contrast, intrinsic self-healing constructs dynamic bond networks via rational molecular design, enabling repeated cyclic healing and overcoming the drawbacks of extrinsic approaches. Compared with rubbers and epoxy resins, polyurethane (PU) elastomers exhibit superior compatibility with dynamic bond networks due to their exceptional molecular designability, making them the preferred substrates for integrating self-healing functionality. Meanwhile, they combine high elasticity, excellent mechanical strength, and good weather resistance, and have found extensive applications in mechanical equipment, aerospace engineering, and other industrial sectors. Nevertheless, they remain susceptible to performance failure induced by external mechanical damage. This study uses a systematic analytical framework covering dynamic bond network design, performance regulation, and scenario adaptation. The self-healing mechanisms, synergistic effects, performance-optimization strategies, and application-scenario requirements of dynamic bond-based self-healing systems are also described. The applications of intrinsic self-healing PU elastomers in fields such as wearable electronics and adhesives are reviewed, and key challenges including the trade-off between conflicting properties and poor environmental adaptability are highlighted. This work aims to provide a valuable reference for the development of function-oriented self-healing PU elastomers.