Adhesion and sliding of snow on hydrophobic solid surface

The relationship between hydrophobicity and snow adhesion or snow sliding on various hydrophobic silica films was investigated. A super-hydrophobic film showed an excellent anti-snow adhesion property against both dry and wet snow, and a sliding acceleration of dry snow. However wet snow showed poor sliding behavior on the film, hydrophilic smooth glass surface being thus effective only for sliding of wet snow. It is deduced from experiments, utilizing water-hollow glass beads composite, that sliding behaviors of the composite on a super-hydrophobic surface depended on the solid concentration and was limited by line tension (solid < 40%), viscous flow (40% < solid), and solid-solid friction (solidsimilar to100%). Based on the practical exposure results, it can be regarded that dry snow and wet snow are in solid-solid friction limited region and viscous flow limited region, respectively. The sliding of wet snow for hydrophilic surface might be limited by water film formation, and that for hydrophobic surface might be limited by viscous flow.