The Application of Inelastic Electron Tunnelling Spectroscopy to Epoxide Adhesives

Abstract The theory of inelastic electron tunnelling spectroscopy (IETS) and the suitability of this technique for examining adhesive-aluminium oxide interfaces are discussed. IET spectra are presented of an epoxide resin (the diglycidyl ether of bisphenol A), two aliphatic amine hardeners (di-[1 -aminopropyl-3-ethoxy] ether and triethylene tetramine), and mixtures of resin and hardener before and after subjection to the usual heat curing schedules. These show that the curing reaction does not take place within an IETS junction; a possible reason for this is the epoxide resin is physically adsorbed on to the aluminium oxide surface whilst the hardeners may be chemically adsorbed through the amine groups.