2D Graphene Oxide and MXene Nanosheets at Carbon Fiber Surfaces

Carbon fibers, known for their high strength-to-weight ratio and thermal and chemical stability, are key components in advanced structural composites. The control of the fiber-matrix interface is key to achieving the required physical performance. Functional two-dimensional (2D) materials can conformally coat the fiber surface, facilitate interface and interphase engineering, enhance mechanical properties, and add functionalities. Understanding how 2D flakes bond, integrate, and perform at carbon fiber interfaces is critical to developing multifunctional high-strength composites. Using in-depth multimode scanning microscopy, our study focuses on the surface interactions of graphene oxide (GO) and Ti₃C₂T<i>_x</i> MXene nanoflakes at the surface of low-tension carbon fibers with and without amine functionalization. Our findings suggest that beyond strengthening the interfaces, GO and MXene also provide efficient charge transfer. MXene, in particular, enhances the fiber surface’s electrical conductivity, broadening potential applications of composites to broad areas, including structural supercapacitors and battery cooling/packaging materials. The modification of fibers with GO and MXene not only opens doors for increased interfacial adhesion in composites through enhanced surface roughness but also serves as anchors for bonding, energy dissipation, charge transport, and local interface stiffening, thereby significantly enhancing the properties of the carbon fiber interfaces.