A fluorine-free and high-robustness photothermal self-healing superhydrophobic coating with long-term anticorrosion and antibacterial performances

Superhydrophobic surface is a promising strategy for antibacterial and corrosion protection. However, the use of harmful fluorine-containing materials, poor mechano-chemical stability, the addition of fungicides and poor corrosion resistance often limit its practical application. In this paper, a high-robustness photothermal self-healing superhydrophobic coating is prepared by simply spraying a mixture of hydrophobically modified epoxy resin and two kinds of modified nanofillers (carbon nanotubes and SiO2) for long-term anticorrosion and antibacterial applications. Multi-scale network and lubrication structures formed by cross-linking of modified carbon nanotubes and repeatable roughness endow coating with high robustness, so that the coating maintains superhydrophobicity even after 100 Taber abrasion cycles, 20 m sandpaper abrasion and 100 tape peeling cycles. The synergistic effect of antibacterial adhesion and photothermal bactericidal activity endows coating with excellent antibacterial efficiency, which against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) separately reaches 99.6% and 99.8%. Moreover, the influence of modified epoxy resin, superhydrophobicity, organic coating and coating thicknesses on the anticorrosion of magnesium (Mg) alloy is systematically studied and analyzed. More importantly, the prepared coating still exhibits excellent self-cleaning, anticorrosion and antibacterial abilities after 20 m abrasion. Furthermore, the coating exhibits excellent adhesion (level 4B), chemical stability, UV radiation resistance, high-low temperature alternation resistance, stable heat production capacity and photothermal self-healing ability. All these excellent performances can promote its application in a wider range of fields.