Cooperative mechanisms of tri-component surfactant assemblies in tailoring interfacial wettability during carbon fiber metallization

Carbon fiber, known for its high strength-to-weight ratio, faces limitations in electronic applications due to inherent hydrophobicity and poor conductivity. While copper electroplating enhances conductivity, conventional processes encounter the “black core” defect, where surface-only deposition creates performance inconsistencies. This study innovatively addresses this challenge through electrolyte wettability optimization, rather than traditional fiber roughening. Three surfactants—SDS (anionic), SDBS (anionic), and CTAB (cationic)—were systematically investigated for their synergistic effects on surface tension reduction and plating uniformity. Employing the Taguchi orthogonal design (L9), optimal concentrations were identified as 0.3 g/l SDS, 0.2 g/l SDBS, and 0.3 g/l CTAB. The formulation achieved remarkable improvements: surface tension decreased by 42% (with CTAB being the most effective), contact angle reduced from 82° to 54°, and synergistic surfactant interactions minimized charge neutralization. Microscopy analysis confirmed complete copper coverage across fiber surfaces without black core formation, accompanied by a 302% weight gain. This surfactant-mediated approach establishes a safer, more efficient electroplating strategy for carbon fibers, demonstrating both fundamental insights into interfacial engineering and substantial potential for electromagnetic shielding applications.