Ice accretion on superhydrophobic insulators under freezing condition

Surface icing of insulators causes serious problems such as tower collapse and power failure. Superhydrophobic (SHP) surfaces are attractive candidates to realize anti-icing as its water repelling property. This article studies the effects of SHP coatings applied on glass and insulators under freezing conditions in an artificial climate chamber. Compared with the bare glass and RTV coated glass, the SHP surface could effectively reduce the freezing area and accumulation of ice. The bare insulators were soon covered with a thick layer of ice, whereas only isolated ice points formed on the SHP insulators. The critical droplet diameter is about 40 times smaller for the as-prepared glass surface (121.4 mu m at alpha = 90 degrees) than for the bare glass slide (4.9 mm at alpha = 90 degrees). Therefore, the tiny water droplets on the SHP surface can easily aggregate into large droplets, and roll off before freezing, thus reducing ice accumulation. Besides, the anti-icing behavior of SHP surfaces considerably depends on the tilting angle. With a higher inclination, the water droplets are easier to roll off the surface by gravity. The anti-icing property of as-prepared samples is mainly attributed to the superhydrophobicity of the coatings, which was obtained by a simple nanoparticle filling method. The added nanoparticles can coarsen the surface and contribute to the superhydrophobicity of the coatings. Moreover, the self-cleaning property and durability of the SHP surface were analyzed by corresponding methods. (C) 2015 Elsevier B.V. All rights reserved.