IR STUDIES OF ADHESION PROMOTERS .1. METHOXYTRIMETHYLSILANE ON SILICA AT THE SOLID-LIQUID INTERFACE

The adsorption of methoxytrimethylsilane on silica immersed in heptane or carbon tetrachloride primarily involves hydrogen-bonding interactions between surface silanol groups and the O atoms of MeOSiMe(3) molecules. A 1:1 interaction is dominant for isolated SiOH groups but adjacent interacting pairs of silanol groups adsorb a single silane molecule at low adsorbate concentrations, changing to pairs of silane molecules with increasing concentration. Hydrogen-bonded silane is removed from the surface by evacuation at 293 K but removal of solvent initially promotes a low level of chemisorption resulting in -SiOMe and -SiOSiMe(3) on the silica.