Force measurements on hydrophobized silica surfaces by using AFM

Abstract

Force measurements between SiO₂ surfaces with and without adsorbed phenyl groups in aqueous media using the atomic force microscope (AFM) are compared. An oxidized silicon tip and an oxidized silicon wafer were hydrophobized with phenyl groups, and the long-range attraction induced by hydrophobation is shown in force vs. distance curves. The observed differences prove that the silanol groups of the unmodified SiO₂ surface are replaced by the phenyl groups.