Plasma polymerized silica (PP-SiO(2)) has been investigated as a surface pretreatment for adhesive bonding of metals. Strength and durability of adhesive joints prepared from PP-SiO(2) coated substrates using aerospace and automotive adhesives is excellent. However, epoxy adhesive systems based on primary amine curing agents do not perform well without further chemical derivatization of the PP-SiO(2). This work discusses the relationship between deposition conditions and primer structure as determined by FTIR and XPS and shows that curing agents containing primary amines are capable of catalyzing hydrolysis of silica in the near-interface regions in the presence of water. This hydrolysis does not occur with dicyandiamide-cured adhesives.