Spray-assembled PDA-PPy nanofiber networks on waste toner for enhanced photothermal conversion and efficient anti-icing and de-icing

Solar-driven materials are regarded as one of the key approaches to effectively utilize clean energy. However, the existing materials are limited by the intrinsic optical absorption characteristics, which restricts the improvement of photothermal conversion efficiency. Herein, multi-scale polydopamine-polypyrrole (PDA-PPy) nanofiber that was favorable for light trapping, was grown on the surface of waste toner via spray-assisted self-assembly technique. The synergistic effect between the intrinsic material properties of waste toner and the multi-scale PDA-PPy nanofiber structure not only significantly improved the photothermal conversion efficiency but also increased the ice nucleation energy barrier and extended the ice-formation time. The coated glass slide attained a surface temperature of 92.4 °C under 1.0 sun. The coating exhibited a high contact angle (CA) of 165° and an ultra-low sliding angle (SA) of only 2.5°. Furthermore, the freezing time of water droplets on the coated glass slide was delayed by 16.7 times at −5 °C and completely melted within 81 s under 1.0 sun. In addition, the coating still exhibited excellent superhydrophobicity after undergoing tests for mechanical and chemical stability. More importantly, the anti-icing performance of the horizontal cable showed that at −10 °C, no icing was observed on the coated cable within 80 min, while extensive icicles had formed on the surface of the uncoated cable. This multifunctional photothermal superhydrophobic coating had excellent environmental adaptability and long service life, and could be effectively applied to anti-icing protection of outdoor infrastructure.