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 degrees) remained after 200 wear cycles. The coating could repair scratches for only 5 min at 80 degrees 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.