Thermal transport across flat and curved gold-water interfaces: Assessing the effects of the interfacial modeling parameters.

Abstract

The present investigation assesses a variety of parameters available in the literature to model gold-water interfaces using molecular dynamics simulations. The study elucidates the challenges of characterizing the solid-liquid affinity of highly hydrophilic gold-water interfaces via wettability. As an alternative, the local pairwise interaction energy was used to describe the solid-liquid affinity of flat and curved surfaces, where for the latter, the calculation of a contact angle becomes virtually impossible. Regarding the heat transfer properties of different interface models (flat and curved), partly conclusive trends were observed between the total pairwise interaction energy and the thermal boundary conductance. It was observed that the solid surface structure, interfacial force field type, and force field parameters created a characteristic bias in the interfacial water molecules (liquid structuring). Consequently, a study of the liquid depletion layer provided better insight into the interfacial heat transfer among different interfaces. By computing the density depletion length, which describes the deficit or surplus of energy carries (water molecules) near the interface, a proper characterization of the thermal boundary conductance was obtained for the different gold-water interfaces. It was observed that the interfacial heat transfer is favored when the water molecules organize in cluster-like structures near the interface, by a surplus of water molecules at the interface, i.e., lower density depletion length, and by the closeness of water to the solid atoms.