Electrical Properties and Photocatalytic Algal Inhibition of KH570-TiO2/RTV Composite Coatings

Room-temperature-vulcanized (RTV) silicone rubber coatings are widely used on outdoor insulators for their excellent anti-pollution flashover performance. However, under hot and humid climates, algal fouling severely deteriorates their surface insulation properties. In this study, a KH570-modified TiO₂/RTV composite coating is developed to simultaneously enhance antifouling and electrical performance. The influence of nano-TiO₂ particles on the photocatalytic algal inhibition and electrical insulation performance of the composite coatings is systematically studied using SEM, photocatalytic degradation tests, algal cell mortality measurements, resistivity and dielectric tests, flashover voltage determination, and leakage current analysis. The results show that after 8 hours of UV irradiation, the photocatalytic degradation rates of the pristine RTV, 1 wt% RTV, 3 wt% RTV, and 5 wt% RTV coatings reach 17.37%, 92.11%, 93.16%, and 96.22%, respectively. The incorporation of KH570-TiO₂ endows RTV with photocatalytic capability to inhibit algal growth, with the 5 wt% RTV sample achieving an algal cell mortality rate of 84.19% after 96 hours of cultivation under simulated natural environmental conditions. In addition, doping with KH570-TiO₂ enhances the electrical properties of RTV, with maximum increases in surface and volume resistivity of 8.36% and 15.64%, respectively. After simulated cultivation with green algae for 96 hours, the wet flashover voltage of the 5 wt% RTV sample increases by 8.1 kV compared with the pristine RTV. The findings provide a feasible strategy for integrating photocatalytic antifouling and insulation reinforcement in RTV coatings, addressing biological contamination and flashover degradation under humid conditions.