Fabrication of a robust superhydrophobic coating exhibiting superior corrosion resistance via spray application technique

Abstract

Superhydrophobic materials often underperform in practical metal corrosion protection owing to the vulnerability of their rough structures. Additionally, stringent fabrication requirements and high production costs further constrain their development. Consequently, enhancing their mechanical stability with adhesives and streamlining their production processes are focal points of interest. In this research, we employed a combination of modified hydrophobic SiO2 particles and epoxy resin to fabricate a durable, abrasion-resistant superhydrophobic coating on a Q235 steel substrate using a one-step spray technique. Throughout the experimental phase, we systematically investigated the ideal ratio of hydrophobic SiO2 particles to epoxy resin within the coating, comprehensively assessing its wettability, mechanical stability, and corrosion resistance. The ideal hydrophobic SiO2 content was found to be 65%, achieving a contact and sliding angles of 158.9° and 4.27°, respectively. This coating maintained its superhydrophobicity after 4.5 m of mechanical abrasion and 40 tape peeling cycles. In terms of corrosion protection, the coating exhibited an impedance two orders of magnitude higher than that of the bare Q235 substrate. It significantly reduced the corrosion current density by two orders of magnitude, with a corrosion inhibition efficiency of 99.36%. Moreover, the superhydrophobic coating retained its properties after 12 h of immersion in strong acids and bases, 30 d in a 3.5 wt% NaCl solution, and outdoor exposure, demonstrating a degree of anti-fouling capability and excellent self-cleaning properties. Notably, the room-temperature, one-step spray method facilitates practical application on various substrates, improving production efficiency and expanding usability.