Durable superhydrophobicity-memory coating with femtosecond laser-structured micro/nanostructures for anti-corrosion applications

Superhydrophobic coatings have important application potential and value in the field of metal corrosion protection. However, the practical application of the superhydrophobic coating is significantly hindered by their poor durability. In this study, a durable superhydrophobic coating with repairable micro/nanostructures is prepared by femtosecond laser directly writing micropillar structures on the surface of thermal-responsive shape-memory materials. The resultant superhydrophobic coating has excellent structural recovery function against mechanical pressing or scratches due to the unique shape-memory ability of the coating. Apart from the healing property, the superhydrophobic coating also has remarkable durability against 400 cycles of tape peeling, 3 kg water flow impact, 250 cm sandpaper abrasion, and immersion in solutions with different pH values for 48 h. This durable superhydrophobicity-memory coating can effectively protect metals from corrosion damage. Take the example of Mg alloy, the low-frequency impedance moduli of the coated sample can be increased by 10 orders of magnitude compared to bare Mg alloy. The coating is able to maintain superhydrophobicity even after being immersed in corrosive solution for 107 days. Moreover, the anti-corrosion property of the coating after mechanical damage can also be recovered by heating treatment. It is anticipated that this durable superhydrophobicity-memory coating prepared in this study can provide important theoretical value and reference basis for promoting the application of superhydrophobic coatings in the field of corrosion protection.