Atomic force microscopy is employed to study the grafting process on a
silica surface of several kind of silane molecules in anhydrous and a
queous solutions: mono- and trichlorosilanes and mono- and triethoxysi
lanes. A systematic study of the adhesive interaction and the friction
behavior is performed. With the anhydrous silane solutions, we show t
hat only the trichlorosilane molecules are able to graft the silica su
rface, while with the aqueous silane solutions, except for the monoeth
oxysilane, the silica surface was always grafted. This study provides
further support of the use of tribological properties to investigate a
surface modification. We show that the influence of the tip velocity
on the friction behavior is a powerful way to discriminate between the
silica surface and the grafted one.