De-icing properties of photothermal superhydrophobic coatings with skeleton-supported hierarchical structure on asphalt pavement

A thermally insulating photothermal superhydrophobic coating (TIPSC) was developed. • Skeleton-supported hierarchical structure enables superior superhydrophobicity. • TIPSC achieves >95% solar absorptance and 49 °C under 1-sun illumination. • Ice adhesion strength reduced to 19.1% and freezing delayed to 128 min. • TIPSC enhances skid resistance and retains durability after wheel abrasion. Ice formation on road surfaces threatens traffic safety and incurs considerable economic costs. Although photothermal superhydrophobic coatings offer a promising solution, they typically suffer from rapid heat dissipation into the substrate and poor mechanical durability, which restrict their practical application on asphalt roads. To address these issues, we report a mechanically durable thermally-insulating photothermal superhydrophobic coating (TIPSC) built around a two-layer architecture. The coating features a “skeleton-supported” hierarchical micro/nanostructure composed of multi-walled carbon nanotubes (MWCNTs) and modified silicon carbide (SiC) particles, integrated with a glass fiber-reinforced epoxy resin insulation underlayer. This unique architecture imparts superior superhydrophobicity to the surface, characterized by a water contact angle of 154.9° and a sliding angle of 3.3°. Under 1.0-sun illumination, the TIPSC surface stabilized near 49 °C. Notably, the insulation layer effectively minimizes downward heat dissipation, extending the cooling time by 300 s compared to non-insulated coatings. Owing to this combination, droplet freezing on TIPSC was postponed to about 128 min (2.76 times that of pure expoxy) and complete photothermally driven ice removal was achieved in 139 s. Furthermore, the superhydrophobicity of TIPSC reduces ice adhesion strength to only 19.1% of the control group, significantly weakening the ice-to-surface bond. Additionally, the TIPSC exhibits exceptional chemical stability and durability, maintaining its superhydrophobicity after prolonged UV exposure, immersion in strong acid/alkali/saline solutions, and a 10-h wheel tracking abrasion test. Owing to the skeleton-supported surface structure, the coating also slightly enhances the skid resistance of the pavement compared to uncoated surfaces. This research provides a facile and effective strategy for fabricating durable, energy-efficient anti-icing coatings for harsh environments.