Hydrophobic Materials Based on Fluorocarbofunctional Spherosilicates

Abstract

Consecutive hydrosilylation-based syntheses were performed of silsesquioxanes containing mixed groups 1H,1H,2H,2H-perfluorooctyl (PFD) or octafluoropentyloxypropyl (OFP) and trimethoxysilylethyl (TMS) in different stoichiometric ratios. The presence of TMS makes it possible to form covalent bonds with substrates due to the reactivity of this group. All obtained derivatives were applied to hydrophobization of glass plates and by comparison of water contact angles (WCA) on modified surfaces the effect of silsesquioxane structure as well as TMS and fluoroalkyl group contents on hydrophobic properties was determined. Moreover, an additional glass plates surface modification was performed in order to obtain superhydrophobic surfaces. Two silica types of different specific surface (300 and 130 m2/g) and particle size (7 and 16 nm) parameters were used in this case for initial surface modification in order to increase its roughness. Irrespectively of particle size of applied silica, a dependence was found between the increase in water contact angle and the number of fluoroalkyl substituents in a molecule.