Reinforcing CFRP composites by formation of tailored interfacial mechanical interlocking structure on carbon fiber surface

For improving interfacial interactions of Epoxy (EP)/carbon fiber (CFs) composites (CFRP), CFs were oxidized, while grapheme oxide (GO) layer was successfully grafted onto CFs surface through bridging effect of polydopamine (PDA) to obtain GO@PDA@CF hybrids, forming rough surface structure of CFs. The smaller epoxy contact angle of GO@PDA@OCFs indicated improving wettability between CFs/EP, while more and bigger EP fragments remained on interlaminar shear fracture surfaces, and CFs were embedded in matrix without obvious gap, indicating significantly enhanced interfacial bonding of composites by forming mechanical interlocking structure. The interfacial strength of composites was thus improved via effective transfer of stress between matrix-fiber at interface.