Evaluation of interface properties of carbon fiber/resin using the full atomistic model considering the electric charge state

Evaluation of interface strength is important in composite material design such as carbon fiber reinforced plastic. Molecular simulation, which considers aspects such as chemical structure, can be used to evaluate the composite interface strength. Therefore, in this study, the interface energies between graphene, considering the electric charge state, and resin (TriA-X polyimide, DGEBA, triethylenetetramine, vinyl ester, and PA6) were evaluated via molecular dynamics simulation. First, the interface energy and experimentally obtained interface strength were compared. Subsequently, the coefficient of determination R² was calculated using linear approximations from the interface energy and interface strength. In addition, the correlation coefficient was calculated and showed a high correlation. Based on this data, it was conjectured that a relationship exists between the interface strength and interface energy. Furthermore, the validity of the relationship magnitude between the experimentally obtained interface strength and the interface energy obtained via simulation was evaluated. Moreover, considering graphene oxidation, the interface energies between the resin and three forms of graphene (functionalized with OH, COOH, and O groups) were obtained, and the effect of various oxidation surface treatments of graphene on their corresponding interface strengths was investigated.