Two geometries of polydopamine synergistically enhance carbon fiber-epoxy interfacial adhesion

This paper first explores the bio-inspired green surface modification of carbon fiber by two geometries of polydopamine (PDA), that is amorphous coating and nanospheres (PDA NPs ). Compared to only amorphous PDA modified fibers, synergistic modification using dual PDA variants is more effective in enhancing fiber strength and interfacial performance of composite. When the reaction time of amorphous PDA on carbon fiber reaches 96 h, it could adsorb more PDA NPs with dense and uniform distribution, which consequently leads to the maximal enhancements of 20.5 % and 64.4 % in fiber strength and interfacial shear strength due to the synergistic effects of improved resin infiltration, barb-like micro-nano interlocking, dynamic hydrogen bonds that repeatedly dissipate energy, epoxy molecules slide along PDA NPs that alleviate stress, and crack defection by dense PDA NPs . This paper highlights an effective and green-initiative avenue for the promising interfacial engineering modulation of high-performance composites.