接着の分子科学

─第一原理計算によるアプローチ─

抄録

Our earlier studies on the adhesion between epoxy resin and aluminum surface (carbon fiber) are reviewed. Mechanistic aspects of the adhesion interaction has been studied by using first-principles calculations. Stable structures of resin-surface complex, adhesion energies, and details about interaction sites are obtained from geometry optimizations for some reasonable models based on first-principles calculations with a plane wave basis set and periodic boundary conditions. Calculations reveal that hydroxyl groups of the epoxy resin interact with the surface of aluminum oxide to form hydrogen bonds, which work as a main force for the adhesion. Plots of energy versus vertical distance of the resin from the surface are nicely approximated by the Morse potential. The force required for detachment of the resin from the surface can be estimated from the maximum value of the force-distance curve, which is obtained from the derivative of the potential energy curve. Surface structures of carbon fiber are modeled by the armchair-edge structure of graphite functionalized with OH and COOH groups. Adhesive properties of the model interfaces are also evaluated based on the binding energy and the maximum adhesive force acting at the interface. Calculated adhesive properties in the two aluminum surface and carbon fiber systems strongly suggest that hydrogen bonds between the oxygen-containing functional groups of epoxy resin and the surfaces play a crucial role in the adhesive interactions.