Study on the Characteristics and Influencing Factors of Hydrophobicity Transfer of Superhydrophobic Coating

Insulators covered with superhydrophobic coatings have better anti-pollution flashover performance. In high-pollution areas, the superhydrophobic coating gets covered with a contamination layer. The droplets are in contact with the contamination layer instead of the superhydrophobic coating. However, there is still a lack of relevant research on the hydrophobicity of the contamination layer. It is not conducive to evaluating the functional performance of superhydrophobic insulators in high-pollution areas. Choose diatomite to simulate contamination. The effects of fouling time, environment temperature, diatomite density, and impurity (NaCl) on the hydrophobicity of the contamination layer are analyzed experimentally. The experiment results show that the diatomite layer becomes hydrophobic over time. The higher the temperature is, the faster the hydrophobicity of the contamination layer will increase, and the higher the peak value of the static contact angle will be. However, the diatomite density and the exitance of NaCl have little influence on the hydrophobicity of the diatomite layer. Furtherly, the composition of the superhydrophobic coating is found in the diatomite layer, which proves the existence of hydrophobicity transfer. According to theoretical analysis, the appearance of transfer will enhance the hydrophobicity of diatomite particles. When the angular coordinate of the liquid-protrusions-gas triple line is greater than 90°, the mechanical conditions for the diatomite particles carried away by the droplet can be satisfied. As a result, hydrophobic diatomite is attached to the droplets’ surface.