Self-propelled drop jumping during defrosting and drainage characteristic of frost melt water from inclined superhydrophobic surface

Drainage behavior of frost melt water from bare, hydrophobic and superhydrophobic surface was experimentally investigated. The self-propelled droplet jumping during defrosting on superhydrophobic surface was captured and the self-drainage characteristic on inclined superhydrophobic surface was observed. In addition, the influence of surface inclined angle on drainage time and surface temperature after complete drainage was analyzed. It is found that the occurrence of spontaneous jumping of defrosted droplet was induced by drop coalescence, which can overcome the surface adhesion, leading to frost melt droplets suspending on superhydrophobic surface. Moreover, the frost melt water can be entirely released with no water droplets retention on superhydrophobic surface at larger than 30° inclined angle, which cannot happen on bare and hydrophobic surface. Furthermore, the surface can keep at low temperature after complete defrosting. The results show that the superhydrophobic surface has an excellent self-drainage capability, which provides possibility for improving defrost efficiency.