The drying of 3-glycidoxypropyltrimethoxy silane

Changes in the FTIR spectrum of 3-glycidoxypropyltrimethoxy silane adsorbed from solution onto FPL-etched aluminum as a function of the drying of the film are reported. These are compared to those obtained from the same molecule in aqueous solution in both its fully hydrolyzed and gelled form. The spectra are also compared to ab initio calculations performed at the 6-31G level of approximation. It is demonstrated that the deposited silane can be divided into a strongly adherent (chemisorbed) form and a weakly adherent (physisorbed) form. The spectra of the latter show extensive reaction between the silanol groups and the epoxy group. The spectra of the former show an almost total absence of such a reaction. Instead, there is extensive Si-O-Si and possibly Si-O-Al bonding. (C) 1998 Elsevier Science B.V. All rights reserved.