Shuang Liang

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.

In this paper, a series of self‐healing waterborne polyurethane/polyacrylate composites (SWPUA) with different disulfide content on the main chain were synthesized. The SWPUAs were synthesized from isophorone diisocyanate, dimethylolpropionic acid, polyether diol and bis(2‐hydroxyethyl) disulfide (HEDS). The structure of the products was characterized by IR and Raman spectra. The effects of different content of HEDS on dispersion stability, mechanical property and self‐healing properties (including tensile strength and breaking elongation) of SWPUAs were studied. The results showed that all the prepared SWPUAs have excellent dispersion stability, thermal stability, self‐healing efficiency and certain hydrophobic capacity. Thereinto, SWPUA‐1 and SWPUA‐2 products with HEDS content of 0.0025 mol and 0.0050 mol have the best repair efficiency. They can recover 101.03% and 102.18%, respectively, after 3 h of repair at 75°C. In addition, SWPUA‐1 has the highest repeatedly repair efficiency of 91% for tensile strength but 75% for breaking elongation because of the influence of physical entanglement and chain link.