Carbon fiber surface modification by ion implantation for interfacial performances improvements of epoxy composites

The effect of ion implantation on interfacial properties of carbon fiber composites was studied by means of a combination of experiments and molecular simulations. In this study, copper ions were implanted into carbon fibers according to the designed technical parameters. Molecular simulation was involved to verify the bidirectional diffusion of copper ions at the interphase during the curing process, accompanied by reverse penetration of epoxy and amino groups into the ion layer. Meanwhile, the treated fiber monofilament can maintain mechanical strength similar to that of commercial fibers. The implanted copper ions were also beneficial to the ring-open reaction of epoxy groups. After ion implantation, the interfacial modulus transition layer of the resulting composites was broadened, leading to a 73.6% increment in the interfacial shear strength compared to that of commercial fibers, which can be ascribed to the modified interfacial interaction between carbon fibers and resin matrix. Therefore, the ion implantation has been proven to be an effective and potential approach in improving the interfacial properties of fiber-reinforced composites. [GRAPHICAL ABSTRACT]