Advances in constructing Carbon Fiber ‐ MXene multilevel structures to reinforce interfacial properties of c arbon fiber reinforced polymer composites

Abstract Carbon fiber reinforced polymers (CFRPs) have received widespread attention due to their excellent mechanical properties. However, the poor interfacial properties between CF and resin matrix urgently need feasible and efficient surface modification strategies of CF to regulate the interface. Due to its unique layered structure and abundant surface groups, MXene has been increasingly used in the field of CFRP interfacial modification in recent years. It possesses the advantages of good stability, large specific surface area, abundant adsorption sites and rich functional groups, which could effectively improve surface polarity, roughness and wettability of carbon fibers, thus enhancing effective interfacial bonding and enabling hierarchical regulation of interface in CFRPs. This paper reviews feasible strategies for constructing CF‐MXene multilevel structures, including electrophoretic deposition, chemical grafting, electrostatic self‐assembly, and sizing coating. Then, the strengthening mechanism involving surface morphology, mechanical properties, and interfacial strength of CFRPs are systematically evaluated centered on interfacial activity, interfacial adhesion, surface roughness and surface energy. Meanwhile, the problems in introducing MXene to CF surfaces and future research directions are systematically prospected. This paper could provide valuable guidance to construct CF‐MXene multilevel structures to reinforce interfacial properties of CFRPs composites, thus realizing hierarchical modulation of CFRPs interfaces. Highlights A feasible strategy for constructing CF‐MXene multilevel structures is built. The main methods for constructing CF‐MXene multilevel structures are provided. Treatment processes and reinforcing mechanisms of CFRPs are evaluated.