Interfacial Phenomena in Adhesion and Adhesive Bonding Investigated by Electron Microscopy

Using electron microscopy techniques described in Chap. 2 , we investigate interfacial phenomena in adhesion and adhesive bonding. Polymer–polymer interfaces formed via interdiffusion are visualized and characterized by EFTEM. Fractographic studies using high-resolution SEM investigate entanglements at the polymer–polymer interfaces, and the adhesion mechanism is discussed about the interfacial entanglements. The effect of surface treatments of polymers for adhesion improvement is studied in terms of the surface roughness and the chemical functionality of the adherend created by the surface pretreatments. We then describe the role of chemical interactions between polymers and metals on bonding by the analysis of fracture surfaces by the STEM-replica technique. Bonding mechanisms of adhesive bonding and recently developed direct bonding of metal and plastic are also investigated by STEM-EELS/ELNES and STEM-tomography. Finally, we evaluate the toughness and durability of adhesive joints between metal and carbon fiber reinforced plastics (CFRP) and discuss the durability of the adhesive bonding.