On the Interaction of Organic Molecules with Metal Oxide Surfaces

In this paper the interaction between organic molecules and aluminium oxide is considered. The overall study concentrates on the chemical interface which is created between an organic layer and aluminium oxide. The knowledge of the composition and structure of hydrated films on aluminium is important for the bonding between aluminium and polymers. Native surface layers on aluminium consist of an anhydrous inner layer of amorphous Al2O3 and an hydrated outer layer, where the outer layer determines the adhesion properties. The pseudoboehmite oxyhydroxide surface can be seen as a model for the chemistry found at the surface of the air-formed film after ambient exposure of the aluminium metal. XPS was used to determine the hydroxyl activity on prepared Al substrates. The studied surface treatments were vacuum evaporated, thermally oxidized, alkaline etched, acid etched and boiled in water. As roughness is important electropolished aluminium samples were used. FESEM, FEAUGER, AFM and XPS were used to see the distribution of the organic molecule over the surface. FTIR-RAIRS was used to study the nature of the interfacial bonding. In this contribution some data about phosphonic acids and carboxylic acids are reported. The bonding of the carboxylic organic molecules was correlated with the presence of OH activity on the Al surface.