Enhancing Resistance to Corrosion and Fouling Using Epoxy Coatings with Superhydrophobic Cells

Abstract

As maritime transport becomes increasingly important, metal corrosion results in significant economic losses. Superhydrophobic materials have significant potential for corrosion prevention. However, poor compatibility between superhydrophobic materials and resin reduces the long-term corrosion resistance. Interfacial strengthening cells (IS-Cells) are designed to maintain superhydrophobicity and retain active hydroxyl groups participating in resin-curing. IS-Cells also contribute to achieving the maze effect. A novel anti-corrosion IS coating is fabricated by compatible IS-Cells and epoxy. IS coatings feature smooth surfaces and vertical compactness, protecting against liquid and gaseous corrosive medium. Strong diffusion resistance and extended diffusion distance ensure long-term corrosion resistance of IS coatings. Approximately 85 µm of IS coatings remain corrosion-free after 112 days of immersion in the NaCl solution. The low-frequency impedance, self-corrosion potential, and self-corrosion current density are 1.68 × 10⁹ Ω cm², −0.0708 V, and 5.38 × 10⁻¹¹ A cm⁻², respectively. IS coatings can also withstand 2400 h of neutral salt spray testing without corrosion in the artificial scratches. Due to the electrostatic repulsion between the hydrophobic C–F chains onto IS-Cells and protein molecules, IS coatings maintain anti-fouling properties after dry-wet immersion tests in the natural marine environment for 90 days. IS coatings show great potential for marine anti-corrosion applications.