Construction of “hard‐soft‐hard” structures with ammonium cerium nitrate/sodium alginate/carbon nanotubes on carbon fiber surfaces for superior mechanical

Abstract The interface between carbon fiber (CF) and the resin matrix is of paramount importance in determining the overall performance of composite materials. This study employed ammonium ceric nitrate (ACN), sodium alginate (SA), and aminated carbon nanotubes (CNTs) to fabricate “hard‐soft‐hard” nanostructure on the surface of CFs with the aim of enhancing the interfacial properties of the composites. The results indicated that interlaminar shear strength (ILSS), interfacial shear strength (IFSS), flexural strength, and modulus of the composites demonstrated a respective increase of 31.0%, 51.8%, 44.3%, and 85.3% following the modification process. The observed positive outcome can be ascribed to the creation of “hard‐soft‐hard” nanostructures achieved by the combination of ACN, SA, and CNTs through both hydrogen and covalent bonding. The nanostructures serve to augment the surface chemical activity of the fibers and amplify the specific surface area, thereby facilitating enhanced mechanical interlocking between the fibers and the resin. Furthermore, the composites of CF prepared through this method demonstrate outstanding mechanical characteristics, rendering them appropriate for the construction of longer‐lasting and more resilient wind turbine blades. Highlights ACN, SA, and CNT create a “hard‐soft‐hard” multi‐phase structure. ACN/SA/CNT synergistically enhances composite interfacial bonding. Inorganic–organic–inorganic materials on CF form novel interfacial phases. Resultant structure improves composite interface properties.