Effect of Modifying Group Size and Type on the Morphological and Functional Characteristics of Hydrated Silica

Materials based on hydrated silica containing organic groups of varying nature and size were obtained, including hydrophobic hydrocarbon groups (vinyl- and dodecyl-) and fluorine-containing groups (3,3,3-fluoropropyl- and 1H, 1H, 2H, 2H-perfluorodecyl-), as well as hydrocarbon groups containing proton-acceptor groups (3-aminopropyl- and 3-(phenylamino)propyl-). The thermal stability of the resulting materials was demonstrated up to temperatures of 300°C. The introduction of small hydrophobic fragments onto the silica surface provides highly dispersed materials with specific surface areas reaching up to 675 m2/g. Increasing the size of the hydrocarbon or perfluorinated groups leads to the formation of superhydrophobic materials exhibiting water contact angles as high as 174°. It was shown that the incorporation of silica modified with 1H, 1H, 2H, 2H-perfluorodecyl groups into a styrene–ethylene–butylene–styrene block copolymer matrix enhances the hydrophobicity of the resulting films from 105° to 137°.