The fluorinated SiO2 self-assembly surface of epoxy resin with excellent insulating and superhydrophobic properties

The flashover and dampness on the surface of epoxy resin (ER) composites are two critical factors leading to the failure of high voltage direct current (HVDC) insulating devices. Designing and constructing a surface structure with high insulating and hydrophobic performance is an effective way to solve these problems. In this paper, we prepared fluorinated silica nanoparticles (F-SiO2) using a combination of dielectric barrier discharge (DBD) plasma and 1H,1H,2H,2H-Perfluorodecyltrimethoxysilane (FAS-17). The resulting low-surface-energy F-SiO2 self-assembled on the surface of ER to form a thin layer structure. Our results demonstrate a significant improvement in both the surface flashover voltage and hydrophobicity of ER composites with the self-assembly structure. The maximum surface flashover voltage is increased by 35.73% to 12.08 kV, and the maximum water contact angle reaches superhydrophobicity at 155.5 +/- 3 degrees. The improvements in flashover voltage are attributed to changes in trap energy level and surface roughness. At the same time, the superhydrophobicity is due to the low-surface-energy characteristics and micro-nano structure of the self-assembly structure. This study provides a promising approach for synergistically improving flashover voltage and hydrophobicity of insulating materials.