Spectral analysis of thermal boundary conductance across solid/classical liquid interfaces: A molecular dynamics study

We investigate the fundamental mechanisms driving thermal transport across solid/classical-liquid interfaces via non-equilibrium molecular dynamics simulations. We show that the increase in thermal boundary conductance across strongly bonded solid/liquid interfaces compared to weakly bonded interfaces is due to increased coupling of low-frequency modes when the solid is better wetted by the liquid. Local phonon density of states and spectral temperature calculations confirm this finding. Specifically, we show that highly wetted solids couple low frequency phonon energies more efficiently, where the interface of a poorly wetted solid acts like free surfaces. The spectral temperature calculations provide further evidence of low frequency phonon mode coupling under non equilibrium conditions. These results quantitatively explain the influence of wetting on thermal boundary conductance across solid/liquid interfaces. (c) 2014 AIP Publishing LLC.