Constructing industrial lignin into robust and multifunctional superhydrophobic coating for effective anti-icing

Using renewable materials as primary components for constructing superhydrophobic coatings is an effective strategy for enhancing the environmental sustainability of anti-icing technologies. Alkali lignin, a by-product of the pulp and paper industry, was graft-modified with 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane to create a robust and multifunctional superhydrophobic coating for effective anti-icing. The results demonstrated that the industrial lignin-based coating achieved a contact angle of 162.1°. Its robustness was evidenced by the fact that the contact angle showed no significant change after 400 vertical drop hammer impacts (with 100 g weights) and 900 cm of abrasion with 800-grit sandpaper. Furthermore, the coating versatility was confirmed through excellent self-cleaning properties, ultraviolet (UV) aging resistance, high-temperature durability, and substrate applicability. These characteristics provided a solid foundation for use of anti-icing coatings in extreme environmental conditions. More importantly, the superhydrophobic aluminum alloy samples exhibited outstanding anti-icing properties, as confirmed by low-temperature freezing delay and durability tests. The freezing time of the water droplets on the aluminum alloy sample was extended threefold, and the coating remained superhydrophobic for 10 days at -24 °C. This study offers new insights into the development of environmentally friendly anti-icing coatings and the value-added utilization of industrial lignin.