Bio-inspired self-healing MXene/polyurethane coating with superior active/passive anticorrosion performance for Mg alloy

• A room temperature self-healing MXene/polyurethane coating was developed. • Prepared PU polymer can self-heal at room temperature and saltwater. • The coating integrated inhibiting effect, barrier properties and self-healing function. • f-MXene@PU coating exhibits ultra-low corrosion current density and high self-healing efficiency. The presence of micropores/cracks and the poor self-healing performance cause the organic coating to degrade its protective ability during long-term corrosion. In this work, a bio-inspired anticorrosion coating has been successfully fabricated on Mg alloy, which exhibits superior active/passive corrosion protection and self-healing performance. The polyurethane (PU) with synergistic effect derived from disulfide bond and hydrogen bond can self-repair at ambient temperature. The methionine functionalized Ti 3 C 2 MXene (f-MXene) can form hydrogen bonds with self-healing PU matrix and remarkably improve the active/passive anticorrosion properties, which can be ascribed to the corrosion inhibition and labyrinth effect. Based on the electrochemical tests, the f-MXene doped PU (f-MXene@PU) coating displays excellent anticorrosion performance with an ultra-low current density value of 5.107×10 -11 A cm -2 . Besides, the f-MXene@PU coating possesses a remarkable anticorrosion self-healing efficiency of 140%, as compared to the as-reported traditional intrinsic self-healing polymers with a maximum repair efficiency of 100%. Combining with the triple effects of active (inhibiting effect) and passive (barrier performance) anticorrosion and self-healing functions, it can provide a green and facile synthesis strategy for constructing self-healing coating with the excellent anticorrosion properties.