NIR-triggered self-healing SiO2/melanin coatings with enhanced corrosion-resistant and mechanical robustness

Polymer coatings are inherently susceptible to deformation and irreversible damage when they are subjected to external forces during service. Self-healing coatings integrated with exceptional mechanical robustness and corrosion resistance are essential for industrial applications but have been deemed challenging. Here, we present a NIR-triggered self-healing coating by combining a toughness epoxy network with melanin-modified silica (MMS). Moreover, to investigate the impact of pore size and porosity of silica on the corrosion protection performance, three types of various silica particles are selected as building blocks. The melanin-modified fumed silica/epoxy coatings demonstrate superior elongation (275 %), outstanding tensile strength (5.31 MPa) and high toughness (7.37 MJ·m3). Moreover, the introduction of the MMS can not only improve the anticorrosion performance (|Z|0.01 Hz value of 1.24 × 1010 Ω·cm2) but also realize fast photo-thermal repair (60 s). Our strategy furnishes a universal layout prototype for the manufacture of robust self-healing coatings with a scalable and cost-effective preparation method.