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Under natural application conditions, water in the forms of condensates and high-speed raindrops tend to form Wenzel contact with the surface of superhydrophobic coatings, and in this case, the effect of the standing water on the abrasion mechanisms of superhydrophobic coatings is not clear. To investigate the issue, comparative tests of abrasion-induced aging on the surface of the superhydrophobic coating under dry, and water infiltration conditions are conducted. A theoretical prediction model of the friction magnitude on the surface of the superhydrophobic coating under the above two conditions is established, and the experimental phenomenon is analyzed based on the theoretical results of the model. The results show that once water wets superhydrophobic surfaces in Wenzel mode, the microscopic rough structures on the surfaces are more likely to fall off under external friction due to the presence of Laplace pressure, which means that the presence of water makes the superhydrophobic surfaces more prone to abrasion-induced aging in this condition. [Display omitted] [ABSTRACT FROM AUTHOR]

Using micro-nanostructure superhydrophobic coating with the unique self-cleaning phenomenon is a feasible method to further reduce the frequency of insulator pollution flashover. However, the research on the anti-pollution flashover performance of superhydrophobic coating is still insufficient. This paper analyzes the various types of forces on the polluted particles accumulated on the superhydrophobic coating surface, and calculates that the vertical force or the horizontal force on the nano-scale and micro-scale particles is positive when they are in contact with most types of droplets. After being fully wetted, these particles are easily absorbed or pulled by the droplets and leave the coating surface. So it is necessary to establish a new DC pollution flashover mechanism model of superhydrophobic coatings surface from the electric field perspective. Based on this model, the relationship between the pollution flashover voltage and the dry flashover voltage is clarified in the state of extremely small leakage current. Furthermore, the anti-pollution flashover performance experiment was carried out on superhydrophobic coating, RTV coating, and uncoated surface to test the leakage current under different conditions. The experimental results show that at any pollution degree, the leakage current of superhydrophobic coating surface always remains about 16.3μA after being completely wetted. [Display omitted] [ABSTRACT FROM AUTHOR]

If the apparent contact angle (ACA) of superhydrophobic materials could be significantly affected by drop volume, it would not be reliable to use ACA as an important index to evaluate the wettability of superhydrophobic materials. In order to explore the effect of drop volume on the ACA of hierarchical structured superhydrophobic surfaces, two kinds of hierarchical structured superhydrophobic surfaces, natural lotus leaf surface and superhydrophobic coating, were used for experimental analysis. In addition, a physical model of ACA considering drop volume was established. And the relationship curve between drop volume and ACA was calculated. The experiment and simulation results show that for each kind of drop, the volume has no significant effect on the ACA of hierarchical structured superhydrophobic surfaces. And the ACA can reflect the wettability of the superhydrophobic material effectively. [ABSTRACT FROM AUTHOR]