Intermediate-layer strengthened superhydrophobic coating with stable corrosion resistance, delayed icing and long-term weatherability

Abstract

Improving the mechanical stability and anti-corrosion durability of superhydrophobic material remains a great challenge that has not been solved. In this paper, we designed and prepared two types of superhydrophobic coatings using PTFE nanoparticles and waterborne epoxy resin, viz. superhydrophobic PTFE@epoxy single layer coating and superhydrophobic Epoxy + PTFE@epoxy double layer coating. It was found that the mechanical stability and interfacial bonding of the superhydrophobic composite coatings were further improved by introducing an epoxy resin intermediate layer. The superhydrophobic Epoxy + PTFE@epoxy double layer coating maintained excellent non-wetting superhydrophobicity even after 150 sandpaper abrasion and 160 tape-peeling cycles. The electrochemical testing results showed that the Rct and low-frequency modulus values of the superhydrophobic double layer coating improved by 7–8 orders of magnitude compared with the bare Q235 carbon steel substrate, demonstrating excellent corrosion resistance. In addition, the coating maintains good corrosion protection after 60 days of outdoor atmospheric exposure and 30 days of neutral salt spray acceleration tests, indicating superior weathering resistance and long-term anti-corrosion properties. The coating also features delayed icing, self-cleaning, anti-fouling, chemical stability, and high substrate applicability, which provides long-lasting multifunctional superhydrophobic materials with comprehensive functions.