The reduction in the insulating performances of the insulators of overhead power lines can give rise to critical issues for the transmission and distribution systems. The decrease in the performance of these components is linked in many cases to the presence of pollutants on the surface, due to the deposition of materials, both soluble and insoluble, deriving from the atmospheric aerosol. This research aims to contribute to the development of anti-fouling coatings, to reduce the accumulation of pollutants, with industrially applicable materials and processes.

The hydrophobic approach to anti-fouling, currently applied in the insulators made of polymeric materials, is hereby pursued with the development of silicon based polymeric materials with a liquid hydrophobic filler. The synthesis and chemical-physical characterization of different formulations allowed the identification of two coatings that showed low water adhesion and good capabilities of leaching pollutants. With the aim of obtaining super-hydrophobic surfaces, coatings have also been prepared by depositing thin silicone films with solid fillers, and contact angles of up to approximately 150° have been obtained, however with high adhesion of water.

An approach based not only on surface wettability but also on the photodegradation of organic pollutants has then been introduced. Photocatalytic surfaces based on Ti and Zn oxides have been prepared, obtaining hydrophilic surfaces whose photocatalytic activity towards two organic molecules was demonstrated. The addition of a poly-dimethyl-siloxane matrix or a fluoro-alkyl-silane to the oxides also allowed to obtain hydrophobic surfaces, while maintaining photodegradation capabilities to a good extent. Some of these coatings, deposited by spray-coating, proved to be superhydrophobic, with static contact angles around 160° and hysteresis lower than 10°.

The in-field experimental activity has been carried out, with the evaluation of the performance of a hydrophobic coating applied to glass insulators: after approximately one year of outdoor exposure, the surface contamination levels, measured quarterly, did not differ significantly from those measured on uncoated insulators.

Furthermore, continuity has been given to the chemical analysis activities for the determination of the ionic and metallic fraction of the contaminants, contained in the insulator washing solutions, results consistent with the expected concentrations have generally been found.

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