Pressure Dependence of Thermal Conductivity and Interfacial Thermal Resistance in Epoxy Systems

Thermal management in electronic devices is one of the biggest challenges faced by the semiconductor industry. Thermal Interface Materials (TIMs) are used in electronics to fill air gaps between the surfaces of integrated circuit (IC) chips to dissipate heat. Polymer-graphene composites, a very promising choice as TIMs also have a drawback of high interfacial thermal resistance and a low thermal conductivity of polymer. It is known from the theoretical models that application of pressure may affect the thermal conductivity in a desirable manner, but quantitative simulations were not available. In this paper, the pressure dependence of thermal conductivity of epoxy and interfacial resistance at epoxy-graphene interface is studied using non-equilibrium molecular dynamics (NEMD) simulations. The results show that the thermal conductivity of epoxy increases with increase in pressure, and they compare well with the predictions using a theoretical model. The interfacial thermal resistance at epoxy-graphene interface reduces with increase in pressure. The reduction is sharp in the beginning and slowly reaches saturation as pressure increases. At 10 GPa compressive pressure, a 90-95% decrease in interfacial thermal resistance is observed.