Enhanced anti-icing and anticorrosion properties of nano-SiO2 composite superhydrophobic coating constructed by a large-scale micropillar array approach

Abstract

The ordinary superhydrophobic coating exhibits insufficient anti-icing properties in the low temperature and high humidity environment and poor corrosion resistance after long-term immersion. In this work, the modified nano-silica superhydrophobic coating with the large area micropillar array structure was constructed innovatively on the fluorocarbon varnish coating by a straightforward net embossing method and layer-by-layer assembly techniques to remedy these deficiencies. The anti-icing test results showed that the micropillar array structures could reduce the contact area between water droplets and cold surfaces. It also generates a stronger air cushion effect, which effectively delayed the freezing time and decreased the deicing shear force. Meanwhile, a larger microgroove density per unit area was achieved by reducing the micropillar widths, which further increased the freezing delay time, enhanced icephobic stability, and decreased the deicing shear force. The results of electrochemical impedance spectroscopy test showed that the infiltration of the corrosive medium was delayed by a large amount of air trapped in the microgrooves, so the impedance modulus values were still above 1011 Ω·cm2 after 26 days of immersion in 3.5 wt% NaCl solution. This work provides a new idea for improving the anti-icing properties and corrosion resistance of superhydrophobic coatings by constructing a large area of micropillar array structures on organic coatings.