Adhesion of polymer-inorganic interfaces by nanoindentation

Nanoindentation combined with atomic force microscopy was applied to measur e the fracture toughness of polystyrene/glass interfaces. Film delamination Occurs when the inelastic penetration depth approximately equals or exceed s the film thickness. The delamination size was accurately measured using a tomic force microscopy. Using multilayer indentation and annular-plate anal yses, the interfacial fracture toughness was then assessed. The values obta ined from the two analyses are in good agreement with the fracture toughnes s of the interface being approximately 350 mJ/m(2). By appropriate fracture surface characterization, it was shown that fracture occurs along the poly styrene/glass interface. Crack arrest marks were observed, and their possib le cause discussed. On the basis of the morphology of the fracture surface, the fracture toughness was also evaluated using a process zone analysis. T he result agrees well with those obtained from the other two analyses.