Alkanoic acids adsorb weakly to the native oxide surface of aluminum. Treating the oxide surface first with an alkoxide of zirconium provides for strong subsequent adsorption of the alkanoic acid. The formation of an interfacial zirconium carboxylate gives rise to this strong adhesion. A combination of quartz crystal microbalance and ultrahigh-vacuum IR spectroscopic techniques were used to establish the stoichiometry and structural features of the interfacial zirconium carboxylate film.