Effects of electrophoretically deposited graphene oxide coatings on interfacial properties of carbon fiber composite

Graphene oxide (GO) was utilized to improve the interfacial performance of carbon fiber (CF) and epoxy resin. In this work, a simple and an effective way, without complex chemical reactions and long processing time, is proposed to prepare GO/CF hybrid fiber via electrophoretic deposition (EPD). In this method, ultrasonically assisted EPD is employed to deposit GO on CF when oxidized carbon fibers are continuously immersed into GO aqueous dispersion. Surface functional group, surface roughness, and surface morphologies of carbon fibers were examined by Fourier transform infrared spectrometer, atomic force microscopy, and scanning electron microscopy, respectively. Surface free energy of the fiber was characterized by dynamic contact angle analysis. Results show that uniform GO coating with rough morphology can be formed on carbon fibers. Moreover, surface wettability of carbon fibers to epoxy resin is significantly improved by enhanced surface free energy due to the deposition of GO. Meanwhile, the introduction of GO in the carbon fiber/epoxy resin composites results in a 56.1 % enhancement in the interfacial shear strength which confirms the remarkable improvement in the interfacial adhesion strength of the composites. The interfacial fracture mechanism was also analyzed.