The Fabrication And Application Of The Copper Superhydrophobic Surfaces With Spontaneous Motion

The superhydrophobic surface (SHS) exhibited excellent water repellency. This speciality push SHS a broad development prospect, and applied to water harvesting, heat transfer and anti-icing. Many SHSs cannot keep stable Cassie condensation (instability to water vapor) while display superhydrophobic ability to macro drops of water in room temperature. This is the obstacle to commercialization of the SHS.In this research, we used wet oxidation to etch copper and prepare a series of SHSs with different topography, size and condensation behavior. The reaction mechanism of different oxidation process was studied. The microscope was recruited to observe the different water condensation behavior in series of SHSs as prepared. And found the condensed drop in some SHSs can spontaneously move by itself (Cassie condensation) while just growing in others (Wenzel condensation). After studied the relationship between structure and performance, we use the Laplace Pressure to analyze the mechanism of spontaneous moving. And suggested the spontaneous moving of condense should be one of the factor to measure a SHS’s stability on condensation. Finally the SHS with different condensation behavior was used to study the application of anti-icing, water harvesting and heat transfer. The result shows that the SHS of Cassie condensation can delay the icing time, increase the water havesting and enhance the heat transfer efficiency. The Cassie SHS delay the icing time for354mins (-5℃) and37mins (-10℃) compared with copper,302mins (-5℃) and29mins (-10℃) compared with Wenzel SHS. The efficiency of water harvesting was increased by more than70%at superhydrophobic(Cassie condensation)-hydrophobic patterned surface compared with copper surface. And the Cassie SHS raise the outlet temperature for7.5℃with the heat transfer experimental facility.