Condensation Frosting Characteristics of SAM-Coated Nanostructured Superhydrophobic Surface

摘要

The present study aims to experimentally investigate the condensation frosting characteristics of the SAM-coated superhydrophobic surfaces under various environmental conditions. The extensive experiments were carried out under the well-controlled conditions with the surface temperature ranging from -4°C to -12°C, the relative humidity of 60%, and the air temperature of 24°C. The dynamics of condensation frosting was analyzed from the captured images by using CMOS camera. From the results, it was found that even if the substrate remained at a subfreezing temperature, the spontaneous freezing of supercooled condensates did not occur because of the free energy barrier of ice embryo at the interface of the substrate-supercooled droplet. The onset of condensate freezing was also triggered by probabilistic ice nucleation. In particular, the delay of the onset time of freezing was found for the nanostructured superhydrophobic surface and substantially dependent on the coolant temperature. Moreover, it observed the presence of an inter-droplet ice bridging between a frozen droplet and neighboring supercooled droplets.