Bilayer bamboo for photothermal trap and large-scale anti-icing

Ice buildup is a safety hazard for infrastructure, transportation and power lines. However, superhydrophobic anti-icing surfaces as well as traditional mechanical and chemical means can hardly coordinate the high anti-icing efficiency with the durable reusability, energy expenditure or environmental impact. Herein, a sustainable, low-cost and dual-action bilayer bamboo (BLB) sheet is developed by bamboo carbonization and surface hydrogel coating. This BLB laminate consisting of a carbonized bamboo (CB) substrate as photo-absorber and thermal insulator and a gel layer as absorber and heat spreader exhibit highly efficient anti-freezing and de-icing performances by converting solar illumination to heat and ion-specifically inhibiting heterogeneous ice nucleation (HIN). This BLB shows remarkable comprehensive performances of low ice adhesion (τ ice ≈ 0 kPa above −25 °C), good photothermal conversion effectiveness (k T =0.52), great recyclability (switchable dual modes), and enhanced HIN inhibition (T H = −25 °C and t H = 1322 s). We provide the single and synergistic mechanisms governing the photothermal trapping and ion-induced HIN inhibition. We demonstrate the frozen drop melting, ice block self-moving and large-area snow removing efficacy on BLB as a convenient and long-lasting anti-icing biomass-based covering material via laboratory-scale and outdoor experiments.