Environmental testing of hydrophobic fluorosilane-modified substrates

Abstract Surface wettability is one of the key properties in coating science. Development of non-wettable (superhydrophobic) materials is a promising field of study, leading to many potential applications such as anti-icing, drag reduction, anti-corrosive or foul-proof materials. Different approaches to this problem led to several solutions, among which vapor phase modification seems very promising. The effects of such modification were investigated on glass and silica substrates to define changes in surface wettability. The surface was cleaned and activated by low pressure plasma and modified with fluorosilanes. Chosen modifiers were PFOTS and PFDTS. Samples were also tested in different environmental conditions in climate chamber. Obtained materials were characterized by water contact angle (WCA), surface free energy (SFE, van Oss-Good method), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements. The results allowed to define surface wettability, and the impact of temperature and humidity on modified surfaces. Moreover, XPS results enabled to determine chemical composition of surface and AFM was used to analyse substrate roughness change after modification. Conducted studies allow for better understanding of surface properties modelling and also put a light on environmental durability of modified materials like nanocomposites or coatings.