▎ 摘　　要

The development of nanoscale reinforcements, which can tailor the interfacial strength and impart multiple functionalities on carbon fiber reinforced polymer (CFRP) composites, remains a challenge for their large-scale adoption in diverse applications ranging from aerospace to transportation and construction industries. In this work radially aligned graphene nanoflakes (GNFs), grown directly on carbon fibers (CFs) via a simple one-step microwave plasma enhanced chemical vapor deposition method, without any catalyst, were used as a novel nano-reinforcement interface. A remarkable 28% enhancement in the tensile strength of the hybrid fibers was observed via single-fiber tensile strength tests, whereas the interfacial shear strength (IFSS) increased by 101.5%. Our results demonstrate that GNFs not only improve the interfacial strength between the GNFs and the epoxy resin but also enhance the in-plane mechanical strength of the CFs-a well-known problem encountered with the direct growth of carbon nanotubes on CFs. In addition, GNFs provided embedded functionality via increased electrical conductivity (60.5% improvement for yarns and 16% for single fiber) and electrochemical capacitance (157% for yarns). This work indicates the potential of GNFs as an interphase for the simplified and cost-effective production of stronger multifunctional CFRP composite materials.