Photothermal superhydrophobic surfaces with dual self-healing capabilities

Abstract

In this study, superhydrophobic coatings with dual self-healing functions were constructed by spraying fluorosilane-modified SiO2 aerogel powders and multi-walled carbon nanotubes on composite films composed of polycaprolactone and epoxy resin. The synergy between the thermally healable polycaprolactone/epoxy resin layer and the photothermal effect of the multi-walled carbon nanotubes allows the coating to repair scratches on the coated surface under light. The porous surface, composed of fluorinated SiO2 aerogel powders and multi-walled carbon nanotubes, provides surface roughness while acting as a storage site for low surface energy healing agents, creating the conditions for surface chemical energy repair. After oxygen plasma etching, the samples were exposed to a solar intensity for 30 min to restore the superhydrophilic state to the superhydrophobic state. The scratches on the sample surface of about 80 μm can be repaired after 20 min of light exposure. The dual healing of chemical energy and the rough structure of the material surface is expected to solve the problem that superhydrophobic surfaces are prone to damage and fail in practical applications. In addition, the material has excellent antifouling and self-cleaning properties. In synergy with the self-healing properties, the material is expected to be recyclable in the long term.