Bio-inspiredly fabricating the hierarchical 3D porous structure superhydrophobic surfaces for corrosion prevention

Highlights: • We developed a facile combined strategy to create a hierarchical 3D porous structure superhydrophobic surface. • The research results provide a new insight to design some ideal micro/nanostructures for tuning the superhydrophobicity. • The superhydrophobic surface possesses the excellent corrosion prevention capacity. The fundamental investigations on the bio-inspired superhydrophobic surfaces have been developed for decades, and various functional surfaces with the special wettability have been artificially fabricated under the abundant inspirations from nature, yet it do not still break the predicaments of the stagnant applications of superhydrophobic surfaces. Herein, we developed a facile combined strategy of sand blasting and two-step chemical etching for the creation of hierarchical 3D (three dimensional) porous structures on Ti6Al4V substrate, and obtained excellent superhydrophobicity with the apparent contact angle reaching 160° and the contact angle hysteresis of only 3° after the modification of fluoroalkylsilane. This mainly attributed to the hierarchical 3D porous structures possessing the huge porosity, and exhibiting a higher capacity to trap a large amount of flowing air pockets. Furthermore, based on the mechanism of the trapped air layer restricting the transport of Cl⁻, the superhydrophobic surfaces displayed a great corrosion prevention performance with the corrosion current density (i_corr) lowering three orders of magnitude and the corrosion potential (E_corr) increasing 0.26 V.