On wetting behavior of fluorocarbon coatings with various chemical and roughness characteristics

This study aims at analyzing the hydrophobicity of a wide range of fluorine-carbon coatings, from carbon-rich to fluorine-rich materials, carried out within the framework of a search for snow- and ice-repellent materials. A simple model accounting for both surface chemical composition and roughness was applied to evaluate the wettability of various fluorocarbon coatings. Apparent contact angles of water on both smooth and rough surfaces are modeled as functions of the fluorination degree and area fraction of air entrapped into the water-solid interface. It is shown that low-fluorinated C-F coatings are hardly hydrophobic and likely will not provide snow or ice-repellent properties. At the same time, coatings with higher F concentration demonstrate good hydrophobicity, which can be further enhanced by air entrapment into rough surface structures. Thus, as coatings with good mechanical properties, low surface energy and surface roughness governed by deposition parameters, such C-F materials may be of potential use for snow- and ice-repellent purposes.