Thermal Conductivity of Gold–Phenylethanethiol (Au144PET60) Nanoarrays: A Molecular Dynamics Study

Abstract

Solvated nanoarrays of Au144 nanoparticles capped with 60 phenylethanethiol (PET) moieties were studied using reverse nonequilibrium molecular dynamics (RNEMD) simulations. The thermal conductivities of the nanoarrays were computed for two chemically dissimilar solvents. These were compared to an effective medium theory (EMT) model based solely on bulk and interfacial properties and the volume fraction taken up by the particles. The interfacial thermal conductance for isolated particles was also estimated via RNEMD using individual solvated particles in nonperiodic geometries. A strong system-size dependence was found in bulk conductivity calculations, particularly in the polar solvent, dichloromethane, but was found to be unimportant in a second nonpolar solvent (toluene). However, the bulk conductivity of solvated nanoarrays also requires projection to infinite system size. The Au144PET60 particles were found to display a molten core at the temperatures used in this study. Our primary finding is that the volume fraction of the metal particles is the primary variable controlling the thermal conductivity of the nanoarrays and that simulated conductivities are predicted well by the EMT model.