Cation π interactions trigger the oriented assembly of graphene oxide for designing high-performance carbon fiber composites

The realization of carbon fiber composites with both high strength and toughness has been frustrated by the unfavorable interphase. Duplicating the nanostructure of nacre into the interface design of carbon fiber is an ideal route. However, truly constructing a nacre-like interphase on the carbon fiber surface is still one of the key challenges due to the unique nanostructure of the carbon fiber surface. Particularly, an important question is lack of proper and strong adhesion forces to guide the “brick” assembly, and hence the ordered arrangement of the brick phase on the carbon fiber surface is hindered. Therefore, we introduced a novel self-designed “mortar” to trigger the oriented assembly of “brick” (graphene oxide, GO) on the carbon fiber surface for the introduction of a truly bio-inspired interface. Owning to rich π conjugated electron density, GO was promising to align with cation-containing “mortar” along the longitudinal direction. The main driving force was the cation-π interaction, which could afford strong interaction along in-plane direction than other binding forces. Due to the carefully designed interface, the interlaminar shear strength (ILSS), and the toughness of upgraded composites achieved 108 MPa and 46.6 MJm−3. This work provided a new inspiration for designing high-performance carbon-based composites.