Preparation of PVDF-PDMS-SiO2 multi-stage rough superhydrophobic coating with excellent anti-corrosion and drag reduction performance via one-step cold spraying

Suitable superhydrophobic surface micromorphology, which can capture air underwater to form an air film, was used to decrease the solid-liquid contact area between the substrate and water, and thus reduce the intrusion of corrosive media and the resistance of movement. In this research, PVDF-PDMS-PF@μ/nSiO2 (PPPSS) multi-stage rough superhydrophobic coating was prepared on aluminum alloy by one-step cold spraying. Perfluorodecyltrimethoxysilane (PFDT) modified dual-scale SiO2 microparticles were used to provide the desired roughness. Low surface energy polymers polyvinylidene fluoride (PVDF) and polydimethylsiloxane (PDMS) were introduced as the polymer skeleton. The water contact angle of the PPPSS coating was 162.6°, with good superhydrophobicity. The coating exhibited excellent anti-corrosion that |Z|0.01 Hz was still three orders of magnitude higher than the bare substrate after 10 days of immersion. The flow experiment results showed that a maximum of 35 % drag reduction was achieved in Reynolds from 6 × 103 to 4 × 104. The equivalent circuit and drag reduction mechanism of the coatings were further investigated by combining surface morphology and material composition. Besides, the PPPSS coating demonstrated good stability and self-cleaning performance. The large-area superhydrophobic surface made by simple and convenient one-step cold spraying, is expected to have practical applications in marine transportation, underwater mapping, and pipeline transportation.