IR studies of adhesion promoters. Part 2.—Adsorption of an alkyltrimethoxysilane and alkylamino-trimethoxysilane on silica at the solid/liquid interface

Abstract

IR spectra of (MeO)₃SiMe on silica, in two states of hydroxylation immersed in heptane or carbon tetrachloride, and during desorption after removal of solvent, show that hydrogen bonding of (MeO)₃SiMe to two or three SiOH groups at low coverages is replaced by 1 : 1 silanol-silane interactions at high coverage. Adjacent surface silanol groups favour a bidentate interaction, in part involving pairs of silanol groups forming H bonds to single OMe groups. The adsorption of (MeO)₃SiCH₂CH₂CH₂NH₂ favours bi- or tridentate H bonding via OMe groups at low coverages but a single H bond via the NH₂ group of each adsorbed molecule at high coverage.