Efficient NIR and Heat Co‐Triggered Self‐Healing MXene‐Polyurethane Hybrid Coating With Superior Corrosion Resistance

Damage to protective coatings compromises barrier function and causes rapid corrosion of metal substrates, which remains a challenge in the corrosion protection field. Intrinsically self-healing coatings capable of autonomously repairing damage through reversible chemical bonding provide a promising strategy for overcoming this limitation. Herein, a waterborne polyurethane hybrid coating (KMXene-SPU) with outstanding self-healing and corrosion resistance was developed. MXene nanosheets were covalently grafted onto dynamic disulfide bond-modified waterborne polyurethane molecular chains via a silane coupling agent. Under synergistic near-infrared (NIR) and heat stimulation, the 0.7% KMXene-SPU coating achieved rapid self-healing, restoring 89.32% of its mechanical strength, which was significantly greater than that under individual NIR or heat conditions. Tafel and electrochemical impedance spectroscopy (EIS) measurements confirmed the outstanding corrosion resistance; the 0.7% KMXene-SPU coating resulted in the lowest corrosion current density and the highest charge transfer resistance. Moreover, after healing, the scratches on the coating were fully repaired. The robust MXene-SPU interfacial architecture enables uniformly dispersed MXene to efficiently deliver heat to damaged regions. This heat promoted the reformation of dynamic disulfide bonds, thereby promoting crack closure and restoring the mechanical integrity and corrosion resistance. This study provides a new strategy for designing durable, intelligent, and self-healing anticorrosion coatings.