Nano-Fe3O4/chitosan-based superhydrophobic coatings with magnetic oil-water separation and photothermal conversion properties

Superhydrophobic coatings are ideal for industrial applications involving oil spill cleaning, de-icing, anti-fouling, and anti-icing. The majority of current superhydrophobic coating preparation techniques have significant costs and pollute the environment, which are incompatible with the principles of sustainable green development. In this study, we produced a superhydrophobic coating based on the low-cost green material chitosan, Fe3O4 nanoparticles, and octadecylamine, which possesses photothermal characteristics and magnetic oil-water separation properties. Among these, octadecylamine supplied a lower surface energy and nano-Fe3O4 supplied the coating's surface roughness structure. Under simulated sunlight, the fabricated coatings produced a pronounced photothermal effect. The surface temperatures of the polyurethane sponge coating and the cotton fabric coating rose to 144.6 °C and 117.5 °C, respectively, after just 5mins. Furthermore, the coatings can be used for magnetically-driven oil-water separation with a certain degree of recyclability. The oil-water separation efficiency of the coating can reach 92% and above. More importantly, the coating also has excellent mechanical stability and self-cleaning properties. Therefore, this cheap and environmentally friendly nano-Fe3O4/chitosan-based superhydrophobic coating has great potential for application.