Influence of surface energetics of graphene oxide on fracture toughness of epoxy nanocomposites

The effects of the addition of graphene oxide (GO) as a filler for an epoxy matrix have been studied in terms of the surface energy and mechanical interfacial properties of GO/epoxy nanocomposites. The GO surface properties were determined using X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The contact angle was measured by the sessile drop method for the evaluation of surface free energy. The investigated mechanical properties of the nanocomposites included the impact strength, fracture toughness and fracture energy. For the GO-reinforced epoxy resin matrix system, a direct linear relationship was observed between the specific polar components of the surface energy and the mechanical behavior. These results indicate that the mechanical interfacial properties of the GO/epoxy nanocomposites were controlled by the specific polar component including the electron–acceptor and electron–donor parameters.