A mechanically robust superhydrophobic corrosion resistant coating with self-healing capability

Abstract

Conferring self-healing capability represents an effective approach for extending the lifespan of multifunctional superhydrophobic coatings. Presently, reported self-healing superhydrophobic coatings exhibit scratch-healing capabilities ranging from 5 μm to 40 μm. However, achieving large-scale scratch-healing (>100 μm) remains a significant challenge within this research domain. In this paper, we introduces the design and fabrication of a dual-layer self-healing superhydrophobic anti-corrosion coating using polycaprolactone (PCL), EASTMAN Kristalex 3085 resin (EK), epoxy resin (EP), and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDTES) modified silica particles via a facile spray-coating approach. The surface morphology, chemical composition, wettability, self-cleaning, damage-healing, and anti-corrosion behaviors of the coating were thoroughly evaluated. Results demonstrate that the coating exhibits self-healing capabilities across multiple scratch-damage scales (45 μm, 55 μm, and 100 μm), particularly exhibiting superior large-scale scratch-healing ability. Furthermore, the coating displays outstanding corrosion resistance, with the charge transfer resistance (Rct) increasing by nearly 8 orders of magnitude compared to the bare Q235 carbon steel substrate. Although the corrosion resistance of the scratch-damaged coatings significantly decreases, the anti-corrosion capability of the scratch-healed coating is effectively restored to its initial state, showcasing excellent anti-corrosion sustainability. Additionally, the coating demonstrates remarkable mechanical stability, withstanding 90 sandpaper abrasion cycles and 70 tape-peeling cycles.