Thermal Transport in Citrate-Capped Gold Interfaces using a Polarizable Force Field



The interfacial thermal conductance from solvated gold nanostructures capped with sodium citrate was determined using reverse nonequilibrium molecular dynamics (RNEMD) methods. The surfaces of spherical nanoparticles and the (111) surfaces of fcc gold slabs were modeled using the density readjusting embedded atom method (DR-EAM) as well as with the standard embedded atom method (EAM), and the effects of polarizability on the binding preferences of citrate were determined. We find that the binding configurations of citrate depend significantly on gold surface curvature and are not strongly influenced by surface polarizability. The interfacial thermal conductance was also determined for the spherical nanoparticles and (111) surfaces, and we find that applying DR-EAM increases the interfacial thermal conductance for systems with spherical nanoparticles much more sharply than for systems with (111) surfaces. Through analysis of excess charge density near the interface, we find that inclusion of polarizability has a larger impact on image charge creation in nanospheres than it does for the planar (111) interfaces. This effectively increases the interaction strength to polar species in the solvent, yielding larger interfacial thermal conductance estimates for the nanospheres.


Supplementary material

Supporting Information: Thermal Transport in Citrate-Capped Gold Interfaces using a Polarizable Force Field
This supporting document provides details of the force field parameters, information on simulation construction and composition, and equilibration details for systems described in the accompanying paper. We also include representative non-equilibrium thermal profiles for the systems as a function of simulation time, and vibrational power spectra for interfacial solvent allowing for comparison between the citrate solutions and neat water.