Improvement of Surface Electrical Properties of Silicone Rubber Based on Fluorination

Fluorination is a critical surface modification technique for enhancing the electrical performance of composite insulators. This study employs molecular simulations to examine the microstructure and space charge behavior of fluorinated and non-fluorinated silicone rubber under an electric field, with experimental validation. The results show that fluorinated silicone rubber exhibits lower total energy, higher polarization, and stronger dipole moments compared to its non-fluorinated counterpart, shifting the material from an insulating to a conductive state. Under lower electric field strengths, the carbon-silicon bonds in fluorinated silicone rubber are longer, but it maintains geometric stability under higher fields. The energy gap changes across different fluorination modes and varies with electric field strength, indicating that fluorination affects conductivity differently at various field intensities. Both fluorination methods improve conductivity in the 0–3.8 V/nm range, with substitutional fluorination showing superior performance between 3.8 and 8.9 V/nm. Above 9.1 V/nm, fluorination maximizes conductivity. The fluorinated samples exhibit a greater redshift at higher electric fields, resulting in enhanced conductivity and improved surface charge distribution. These findings offer insights into the microscopic effects of fluorination on silicone rubber’s electrical properties, while experiments confirm that fluorination increases hydrophobicity and boosts DC flashover voltage, further enhancing the material’s performance.