Dynamic changes of hydrophobic behavior during icing

Abstract

Superhydrophobic surfaces with large contact angles (CAs) and small sliding angles (SAs) are used in many applications such as wings of airplanes or engine front cones to reduce air crashing caused by icing. Most anti-icing studies have mainly focused on the icing behavior on surfaces with specific hydrophobic properties but there have been fewer investigations on the dynamic change of hydrophobicity of the materials during the icing process. In this work, micro/nano structures are prepared on stainless steel by laser etching and modified with a fluorine-doped diamond-like carbon (F-DLC) coating to produce a superhydrophobic surface. The dynamic behavior of the wetting state and icing of water droplets on the F-DLC surface during cooling are studied. As the temperature drops, the hydrophobicity of the surface decreases significantly before freezing and the rate of decrease is related to the temperature and environmental humidity. Water vapor condenses to droplets on the micro/nano structured surface consequently weakening the function of the rough structure and deteriorating the coating hydrophobicity. The results provide a deeper understanding of the dynamic changes of super-hydrophobicity during the icing process.