Multilevel superhydrophobic fin-like microstructure with excellent abrasion resistance and drag reduction via high-accuracy femtosecond laser etching

In this study, we have designed a biomimetic fin-like structure to enhance drag reduction performance with a combination of femtosecond laser etching and simple spraying method. The first part of the research focuses on laser etching with overlap pattern to create fin-like microstructure on the samples, spaced 30 μm apart. Then, a simple spraying method was applied to prepare coatings with a thickness of approximately 13.5 μm on the microstructure. The second part of the study aims to evaluate the hydrophobicity, drag reduction performance and durability of the fin-like structure produced by this composite method. The superhydrophobic surface displays a maximum water contact angle of 161.6° and a roll-off angle of less than 4.6°. The drag reduction performance, as measured by the rheometer test, reaches a maximum of 23.3 %. Furthermore, the micro-scratch test indicates that the composite method improves the adhesion between the coating and the substrate, resulting in enhanced abrasion and corrosion resistance of the superhydrophobic fin-like structure.