Fluorine-Free and Robust Photothermal Superhydrophobic Coating Based on Biochar for Anti-/De-Icing

Environmental pollution can be caused by the improper disposal of agricultural waste and the use of fluorinated chemicals. Icing is a natural phenomenon, but the accumulation of ice on the surface of electrical equipment can damage the equipment and reduce power generation efficiency. Preparation of biochar anti-icing coatings with a fluorine-free process promotes resource utilization and environmental protection. In this study, superhydrophobic coatings with photothermal effect prepared based on biochar as a filler, which was blended with multi-walled carbon nanotubes (MWCNTs) and polyurea adhesive. The coating exhibits remarkable durability, as well as anti-icing, antifrosting, and self-cleaning characteristics. Utilizing fluorine-free chemicals enhances the environmentally friendly nature of the coating. The coating exhibits a contact angle of 155°, and the temperature can increase to 47.6 °C within a duration of 10 min. It can complete ice detachment in 128 s and defrosting in 210 s. The coating demonstrated exceptional durability when exposed to mechanical abrasion using sandpaper and steel brushes, water jet impact, acid and alkali corrosion, and tape-peeling tests. This study streamlines the procedure for creating photothermal superhydrophobic coatings, which contributes to environmental conservation and sustainable development. Additionally, it broadens the possibilities for recycling and reusing rejected crops.