Molecular Dynamics Investigation on the Interface of Graphene/Epoxy Resin Composites by Vacancy Defects and Aluminum Atom Doped

The thermal conductivity of the interface between epoxy resin and graphene is important. Adding graphene to epoxy resin is an important way to improve the thermal conductivity of the interface and holds a long-term expectation for the related research. As a supplement, this work analyzed the effects of single vacancy (SV) defects, aluminum (Al) atom doped and doped around single-vacancy defect (Al3V) graphene on the heat transfer of composite materials. First, graphene/epoxy resin models were built with Materials Studio. The radial distribution function of carbon and nitrogen and the density distribution along the z direction in each model were estimated. Then, the interfacial bonding strength of each model was described by non-bond energy, interaction energy, and hydrogen bond number. Finally, thermal conductivities of bulk material and defective graphene/epoxy resin composites were predicted in LAMMPS with non-equilibrium molecular dynamics method, and the corresponding temperature dependence was analyzed. The results show that the report of van der Waals forces intrigues the ideal interface bonding effect of g-Al3V/EP followed by g-SV/EP and g-Al/EP by the decreasing order. At the defect concentration of 4%, the interface thermal conductivity of the Al3V composite could reach as high as 120.61 MW·K−1·m2, more than three times that of pristine graphene composite. Meanwhile, the minimal enhancement belongs to g-Al/EP’s 48.76 MW·K−1·m2 under 2% concentration. This work is expected to offer a reference for the further research.