Computational studies on polymer adhesion at the surface of gamma-Al2O3. I. The adsorption of adhesive component molecules from the gas phase

We calculate the minimum energy paths and reaction energies of the adsorption of the epoxide adhesive components diglycidylesterbisphenol A (DGEBA), diethyltriamine (DETA), and the adhesion promoter 3-aminopropylmethoxysilane (AMEO) at two different sites on a model of the native Al2O3 surface, using the nudged elastic band algorithm in conjunction with self-consistent charge-density functional based tight binding. Our results show that the chosen combination of methods is well suited to obtain an overview of the reaction mechanisms and kinetics of the adsorption of organic molecules on inorganic surfaces. The obtained MEP-s show that there is preference for the adsorption of the adhesion promoter, AMEO, over the resin, DGEBA, while the adsorption of the curing agent, DETA, is unfavorable. Our approach also gives an insight into the ranges of the mechanical and electronic influences of the adsorption process on the interface, which neither full ab initio methods nor force field approaches can provide. These results will help to develop a quantum mechanics-molecular mechanics multiscale embedding scheme for more detailed studies of organic/inorganic hybrid interface reactions.