Influence of alternating current (AC) corona discharge on the superhydrophobicity of SiO2/fluorosilicon resin nano-composite coating

Superhydrophobic surface is ideal for outdoor insulation due to its low surface energy and excellent self-cleaning ability. However, superhydrophobicity would become weak or lost under corona discharge, which is inevitable in high voltage transmission lines. Composite superhydrophobic surface was fabricated with fluorosilicone resin and silica nanoparticles. It was transformed to superhydrophilicity under corona discharge, but it could recover superhydrophobicity under low intensity corona discharge. Electrostatic charges were proposed to result in temporary superhydrophilicity. When corona discharge intensity was high, hydrophilic silica particles covered with fluorosilicone resin were exposed to air. Adsorbed water film was formed on the surface and prevented the recovery of superhydrophobicity.