A photothermal self-healing superhydrophobic coating with anti-frosting and anti-corrosion properties

The surface frosting and corrosion of Al alloy limit its diversified application. The self-healing superhydrophobic coating opens a new door for the durability and stability of aluminum alloys. However, it remains challenges to simultaneously achieve efficient self-healing efficiency and strong coating adhesion. Here, a coating with great wear resistance and fast self-healing was constructed by introducing thermodynamically stable coordination bonds and highly mobile hydrogen bonds. The prepared coatings (named Al/ZnO-P.I.Z-FAS@PDA) exhibited excellent wear resistance, the super-hydrophobicity (water contact angle >150°) remained after 200 wear cycles. The coating could repair scratches for only 5 min at 80°C. And chemical damage repair could be achieved with the coating at room temperature for 40 min. This was mainly due to the hierarchical structure of non-covalent bond gradient distribution. Hydrogen bonds facilitate the migration of the fluorine chains, and coordination bonds ensure a tight connection between the coating and the base layer. In addition, the interfacial interactions between the materials in the coating were discussed. Based on the super-hydrophobicity of the coating and the dual repair of physical-chemical damage, the coating exhibits excellent self-cleaning, abrasion resistance, frost and corrosion resistance as well as outstanding frost repair and corrosion repair capabilities. In particular, thanks to the photothermal effect of PDA, the self-healing performance of as-prepared coating could come true under sunlight. The coatings in this paper provide directions for the application of Al substrates under harsh conditions.