Meeting the demands of modern high-voltage transmission line applications requires novel functional coatings that minimize corona discharge losses while providing sufficiently low ice adhesion and adequate corrosion protection. This work presents comprehensive results from an extensive study of superhydrophobic (SHC), superhydrophilic (SPhil), hydrophilic (Phil), and slippery liquid-infused porous surfaces (SLIPSs) under alternating current corona discharge. Our experiments confirm that coatings at both extremes of the wettability spectrum—water-repelling SHC and water-attracting SPhil—can reduce corona discharge currents by two to four times under adverse weather conditions, whereas SLIPS coatings, despite their water repellency, may actually increase corona currents in rainy conditions.
Furthermore, we observed distinct differences in long-term coating stability under harsh corona discharge conditions, including ozone exposure, UV radiation, and ion bombardment. SLIPS coatings rapidly degrade due to depletion of the lubricating layer, while SHC coatings exhibit very slow, yet discernible deterioration. In contrast, Phil and SPhil coatings tend to improve their corona-protective properties upon exposure to corona discharge. Among these options, hydrophilic organosilane coatings offer the best overall balance: they significantly reduce corona power losses, maintain ice adhesion levels comparable to bare wires, and achieve a threefold reduction in corrosion currents. Meanwhile, superhydrophilic coatings demonstrate reduced corona discharge but suffer from increased ice adhesion and corrosion rates.
These findings underscore the importance of selecting and optimizing coatings to suit specific climatic conditions. In regions with significant icing, durable superhydrophobic coatings hold promise, provided further work is done to enhance their longevity. In warmer, humid climates, hydrophilic and superhydrophilic coatings are more suitable. Overall, our results highlight how tailoring surface wettability can mitigate corona discharge and other environmental impacts, paving the way for improved performance and reliability of high-voltage transmission lines.
