INTERACTION OF A MODEL EPOXY-RESIN COMPOUND, DIETHANOLAMINE, WITH ALUMINUM SURFACES STUDIED BY STATIC SIMS AND XPS

The interaction of diethanolamine, a model epoxy resin compound, with aluminium surfaces is characterised using static secondary ion mass sp ectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS). Diethano lamine does not adsorb on gamma-alumina but does adsorb on phosphoric acid anodised aluminium, suggesting that the adsorption site is a Bron sted acid. A static SIMS spectrum is obtained consistent with a proton ated species and the XPS N 1s signal shows two states for the adsorbat e. Diethanolamine on an ion-bombarded aluminium surface does not show the characteristic SIMS spectrum observed with the anodised substrate. It is postulated that the hydroxy groups of the diethanolamine form a dialkoxide covalently bound to the ion-bombarded aluminium. The corre sponding XPS N Is signal showed a single binding energy in the range o f Lewis site interactions on alumina. The interaction of all three fun ctionalities of the diethanolamine with the anodised aluminium surface results in stronger adsorption than for a similar difunctional compou nd, (methylamino)ethanol, indicating that both hydroxy groups are invo lved in hydrogen bonding to surface acid sites.