Thermal Insulation and Superhydrophobicity Synergies for Passive Snow Repellency.

The adhesion mechanisms and fracture mechanics of snow on solid surfaces are complex, making the design of an all-purpose snow-repellent surface that is applicable to multiple real-life situations a considerable and unsolved challenge. In this study, we focus on the most difficult-to-remove snow accretion scenario─the formation of a highly adhesive meltwater ice layer at the snow-solid interface. This ice layer originates from snow melting on an initially above 0 °C surface, followed by refreezing in a subzero environment. The complete removal of this ice layer is especially challenging and usually requires active and energy-intensive methods. By combining the characteristics of thermal insulation and superhydrophobicity on solid surfaces, we successfully prevent snow melting and its subsequent refreezing to this highly adhesive ice layer, enabling the complete passive removal of snow from solid surfaces. Our snow-repellent platform is designed using thin superhydrophobic sheets covering solid surfaces, separated by a thermally insulative layer (air gap or aerogel). In contrast to conventional icephobic surfaces, the synergies between thermal insulation and superhydrophobicity provide a tailored route specifically toward the design of passive snow-repellent surfaces.