Constructing Multi‐Scale Interfaces of Carbon Fibers/Carbon Nanotubes Using Non‐Destructive Rare‐Earth Modification Methods to Optimize the Structure and Interlayer Properties of Composite Materials

To improve the interlaminar properties of fiber‐reinforced resin matrix composites, this study utilized a non‐destructive rare‐earth modification method to construct continuous carbon fiber/carbon nanotubes (CF/CNTs) multi‐scale‐reinforced composites. Raman spectroscopy, Fourier‐transform infrared spectroscopy, x‐ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy successfully verified the multi‐scale structure and surface microstructure of the fibers. This method successfully grafted CNTs onto the CF surface at a high density through coordination bonds without destroying the surface structure, increasing the surface roughness of the CF to 280 nm. Compared with the untreated CF composite (60.54 MPa), the interlaminar shear strength of the modified CF composite (79.29 MPa) increased by 30.97%. Experimental results show that the CF/CNTs multi‐scale structure significantly enhanced the mechanical properties of the composite. In summary, this novel chemical grafting method for CF/CNTs multi‐scale‐reinforced composites offers advantages such as non‐destructiveness, operational ease, low cost, and environmental friendliness. This work provides a concrete method for the preparation and application of CF composites.