The study of frost formation along the horizontal direction on the bionic super-hydrophobic surface

In this paper, the frost deposition phenomena on a cold super-hydrophobic was observed. The experimental results show the way that the frost crystals grow on the super-hydrophobic surface is different to that on the plain copper surface. On the super-hydrophobic part, most of the frost crystals grow along the horizontal direction (parallel to the surface) and finally formed ears instead of the normal vertical direction(normal to the surface) as those on the plain copper surface. In order to explain the phenomena we designed a droplet freezing test on the super-hydrophobic surface and the copper surface each. On the super-hydrophobic surface the frost crystals grow on almost every position of the ice droplet surface. But on the copper surface the frost crystals grow mainly on the top of the ice droplet and along the vertical direction. The frost crystals on the upper position of the droplet thawed and fell down onto the crystals of the lower part of the droplet on the hydrophobic surface more obviously than that on the plain copper surface. The possible theory was proposed to explain the observed phenomena: it may be related to the fact that the electric charge distribution is non-uniform on an isolated conductor surface.