Ice accretion on superhydrophobic aluminum surfaces under low-temperature conditions

An icephobic surface is always desirable for high voltage overhead transmission lines to reduce ice formation on their aluminum surface, especially in a low temperature and high humidity environment. This work studied the effects of two hydrophobic coatings when applied on aluminum surfaces under cold and raining conditions in an artificial climatic chamber. Compared with bare hydrophilic aluminum surfaces, the aluminum surfaces coated with hydrophobic room temperature vulcanized silicone rubber (RTV SR) did resist ice formation but was covered by a layer of ice after 30 min of spraying supercooled water. However, a superhydrophobic coating can largely prevent ice formation on the surface except a few ice growth spots at a working temperature of -6 degrees C. Furthermore, such coating keeps average water contact angles larger than 150 degrees even at a working temperature of -10 degrees C. This highly icephobic performance of the above samples is mainly attributed to the superhydrophobic property of the coating, which was obtained on micronanoscale structured aluminum surfaces after the low surface-energy stearic acid treatment. (C) 2010 Elsevier B.V. All rights reserved.