Strengthen Composite with 3D Aligned Carbon Fiber via Embedded 3D Printing

The orientation of fibrous fillers, induced by shear forces during extrusion, has been demonstrated to significantly enhance mechanical properties, electrical/thermal conductivity, microwave attenuation etc., albeit primarily in a two-dimensional (2D) x-y plane. In this study, we present a novel approach for achieving fiber alignment in a three-dimensional (3D) context, with an emphasis on the Z-direction, by utilizing embedded 3D printing techniques. This process involves the extrusion and suspension of composite inks within a viscoelastic gel medium, during which the alignment of the fiber can be controlled <i>via </i>velocity ratio, nozzle size, fiber dispersion etc. By selectively align the fiber in a 3D pattern, the mechanical properties, and conductivity can be largely improved and tuned.