Enhanced Intrinsic Self‐Healing Performance of Mussel Inspired Coating via In‐Situ Cation Capture

Abstract Under damp or aquatic conditions, the corrosion products deposited on micro‐cracks/pore sites bring about the failure of intrinsically healable organic coatings. Inspired by mussels, a composite coating of poly (methyl methacrylate‐co‐butyl acylate‐co‐dopamine acrylamide)/phenylalanine‐functionalized boron nitride (PMBD/BN‐Phe) is successfully prepared on the reinforcing steel, which exhibits excellent anti‐corrosion and underwater self‐healing capabilities. The self‐healing property of PMBD is derived from the synergistic effect of hydrogen bonding and metal‐ligand coordination bonding, and thereby the continuous generation of corrosion products can be significantly suppressed through in situ capture of cations by the catechol group. Furthermore, the corrosion protection ability can be remarkably improved by the labyrinth effect of BN and the inhibition role of Phe, and the desired interfacial compatibility can be formed by the hydrogen bonds between BN‐Phe and PMBD matrix. The corrosion current density (i_corr) of PMBD/BN‐Phe coating is determined as 7.95 × 10⁻¹¹ A cm⁻². The low‐frequency impedance modulus (|Z|_{f = 0}._{01 Hz} is remained at 3.47 × 10⁹ Ω cm², indicating an ultra‐high self‐healing efficiency (≈89.5%). It is anticipated to provide a unique strategy for development of an underwater self‐healing coating and robust durability for application in anti‐corrosion engineering of marine buildings.