Multilevel Dynamic Interface Engineering for Strong, Tough, and Rapidly Near-Infrared Self-Healing Polyurethane Elastomers

Elastomers that combine mechanical robustness, large deformability, and stimulus-responsive self-healing are desirable for flexible electronics, yet these functions rely on competing requirements for network stability and chain mobility. Herein, we propose a multilevel dynamic interface engineering strategy involving the synergistic incorporation of tannic acid (TA)-functionalized molybdenum disulfide nanosheets (TM) and KH570-modified SiO2 nanoparticles (KSi) into a polyurethane (PU) elastomer, thereby constructing a hierarchical interfacial network that integrates mechanical property improvement and photothermal-responsive repair. The optimized PTM-KSi20 composite exhibits a tensile strength of 21 MPa and an elongation at break of 1811%, corresponding to increases of 98% and 141%, respectively, compared with neat PU. Under near-infrared (NIR) irradiation, PTM-KSi20 undergoes rapid localized heating and achieves a strength-based self-healing efficiency of 92% within 60 min. Furthermore, an AgNW/PTM-KSi20 conductive composite film fabricated using the elastomer as a flexible substrate maintains stable electrical responses. This work presents an effective strategy for simultaneously enhancing the mechanical performance and self-healing functionality of elastomers through multilevel dynamic interface design and provides a promising material platform for durable and self-healable flexible electronics.