Effect of Defects on the Interfacial Thermal Conductance betweenn-Heneicosane in Solid and Liquid Phases and a Graphene Monolayer

The molecular level mechanism of heat transport across the interface between solid and liquidn-heneicosane and monolayer graphene with three types of defects (single-vacancy, multivacancy (MV), and Stone-Wales (SW) (SW1 and SW2 cases are considered based on the orientation of the defects) has been studied using nonequilibrium molecular dynamics simulations. The influence of the alignment of an ideal crystal structure (heneicosane molecules positioned perpendicular and parallel to the graphene basal plane) and two heating modes (in the “heat-matrix” mode, heat enters the defective graphene sheet from one side of its basal plane and leaves from the other side, and in the “heat-graphene” mode, the heat is entering from the heated graphene layer to the cooled heneicosane from both sides of the basal plane) on the thermal conductance has been examined. With an increase in the defect percentage (up to 9.0%), the thermal conductance is found to be increasing for all types of defects under both heating modes. It is observed that both MV and SW2 defects in graphene result in the largest enhancement in the conductance under the heat-matrix mode, whereas the SW1 defect yields maximum improvement under the heat-graphene mode. Spectral analysis indicates that the vibrational modes of all frequencies are important for the interfacial heat transfer.