Spray-coated superhydrophobic surfaces with wear-resistance, drag-reduction and anti-corrosion properties

This paper proposes a facile and low-cost method of preparing superhydrophobic surfaces on aluminium substrates using a two-step spraying method. A layer of hydrocarbon resin adhesive was sprayed on the substrate, after which dichlorodimethylsilane-modified hydrophobic silica nanoparticles were sprayed on the adhesive primer. The surface morphology, wettability and chemical composition were characterized by scanning electron microscope, water contact angle meter and X-ray photoelectron spectroscopy, respectively. The water contact angle of the superhydrophobic surface reached 153.5° ± 1.5° and the sliding angle was 1.8° ± 0.2°. The surface exhibited good wear-resistance in sandpaper abrasion, finger-wiping and knife-scratching tests. Even if damaged, the surfaces could be easily repaired. Rheometry results showed that the surface drag reduction rate reached up to 48.7%. Dynamic polarization tests indicated a great improvement in anti-corrosion properties with a decrease of two orders of magnitude in the corrosion current. The present method can be easily expanded to other materials and does not require special conditions, advanced equipment or complicated preparation processes, making it suitable for mass production.