Advances in effects of carbon fiber surface modification on interface properties of carbon fiber composites

Carbon fiber-reinforced polymers (CFRPs) are extensively employed in high-end applications like aerospace, national defense, new energy vehicles, and high-pressure hydrogen storage, with their global market demand showing robust growth. However, the intrinsic chemical inertness, smooth surface, and low surface energy of carbon fibers (CF) lead to weak interfacial adhesion with resin matrices. This poor adhesion critically restricts the overall mechanical properties of the composites and long-term durability. To address this fundamental challenge, CF surface modification technologies are essential. They enhance interfacial interactions – such as mechanical interlocking, chemical bonding, and improved wettability – by controlling surface architecture (increasing roughness) and chemical composition (introducing active functional groups). These technologies are key to significantly enhancing the interfacial performance of CFRPs and unlocking their broader application potential. This review comprehensively summarizes recent advances in carbon fiber surface modification, focusing on the mechanisms and efficacy of predominant techniques (including liquid-phase oxidation, plasma treatment, chemical grafting, and coating) and their hybrid strategies in improving critical interfacial properties like interfacial shear strength (IFSS) and interlaminar shear strength (ILSS) of composites. Future research should prioritize the establishment of quantifiable structure-property relationships, environmentally benign processes, and multifunctional composite systems capable of withstanding extreme environments.