Breathable Nanorod-Embedded Hierarchical Photothermal Coatings with Anti-Soiling and Safe Thermal Regulation for Efficient Anti-Icing and De-Icing.

Photothermal hydrophobic surfaces offer a promising solution for mitigating ice hazards under low-temperature, high-humidity conditions via solar-driven de-icing. However, surface contamination can compromise photothermal efficiency, while fabric-applicable coatings must also provide flexibility, breathability, durability, and safe thermal regulation (≈50 °C). Current systems require further optimization to balance these demands for practical use. Here, a nanorod-embedded photothermal strategy is presented that integrates superhydrophobicity, anti-icing, and de-icing capabilities with environmental robustness in fabrics. The composite comprises a polypyrrole-loaded cellulose nanocrystal inner layer for photothermal conversion and a fluoroalkyl silane-modified silica top layer for superhydrophobicity. The synergy between hierarchical micro-nano roughness and photothermal activation enables an "external repellency, internal heating" mechanism, effectively overcoming the limitations of passive coatings. This dual-functional architecture achieves a solar absorption rate of 97.2% and reaches 53.1 °C under 100 mW cm⁻ irradiation, while remaining safe for human contact and maintaining breathability (moisture permeability: 6.86 × 10 g·m⁻·d⁻¹). It delays freezing by 417 s at -15 °C and reduces the melting time of an ice cube by 53.2% under 1-sun illumination. The fabric exhibits appreciable chemical stability, abrasion resistance, flexibility, and robustness under extreme conditions, ensuring long-term performance. This work offers a scalable solution for outdoor and personal protective equipment in cold environments.