Nano-level insights on the interfacial wettability of graphene oxide-coated carbon fiber/epoxy composite

Electrophoretic-deposited (EPD) graphene oxide (GO) on carbon fiber (CF) has been tried to improve the fiber/epoxy interfacial properties. However, the nano-level understanding on the mechanisms of surface wettability is still somewhat limited, which will be important to ensure the manufacturing ability of CF composites. In this work, the interfacial wetting behavior was systematically investigated via molecular dynamics simulations (MD). The results show significant improvement in interfacial properties by changing the morphology of GO-modified fiber surfaces. In details, appropriately increasing the deposition thickness, surface roughness, stacking angle and the distribution uniformity of GO sheets could enhance the wettability of the fiber surface, resulting in higher cohesive strength. The variation of bond stretching energy was the main factor that induced the change of the potential energy of the epoxy system during wetting simulations. Moreover, two obvious peaks of angular bending energy were observed at the solid–liquid and liquid–vapor surface, which may provide further insights into the formation mechanism of interfacial tensions.