Synergistic surfactants optimize carbon fiber coating

Carbon fiber is light and strong, making it suitable for aircraft, wind turbines, and medical equipment, but poor conductivity limits its use in electronic applications. This can be remedied with electroplating, which immerses carbon fiber bundles in an electrolyte solution to deposit a thin layer of copper. However, conventional electroplating can result in the black core defect, coating only the outer surface. The uncoated fibers inside can lead to performance inconsistencies.

Traditional methods to address this typically involve fiber roughening through strong acids and high temperatures, posing safety and environmental risks. Zhang et al. prevented the black core phenomenon while avoiding these threats by enhancing the wettability of the electroplating solution, or its ability to stay in contact with the carbon fibers.

The authors determined concentrations of three ionic surfactants that optimally enhanced the wettability of the electroplating solution. Microscopy revealed that carbon fiber prepared in this mixture was fully covered by copper without black core formation.

“This work provides a new approach to solving the black core problem in carbon fiber electroplating,” said author Kai Yu. “It systematically reveals the synergistic mechanism of multicomponent surfactants in the electroplating solution, providing a theoretical basis for interfacial engineering and electrochemical composite treatment.”

This electroplating method could be extended to other structures, such as electromagnetic shielding fabrics and flexible circuits.

“The proposed electrolyte optimization strategy has universality and scalability, which is not only applicable to carbon fibers but also provides a reference for the electroplating treatment of other hydrophobic materials,” Yu said.

Next, the authors will study the cooperative effects of other types of surfactants in electroplating.

Source: “Cooperative mechanisms of tri-component surfactant assemblies in tailoring interfacial wettability during carbon fiber metallization,” Zhe Zhang, Yong Wang, Xiaokang Li, Feng Zhou, Huajuan Jiang, Shangqian Jing, Linjie Shao, Feng Yin, and Kai Yu, AIP Advances (2025). The article can be accessed at https://doi.org/10.1063/5.0291122 .