Molecular-Level Understanding of Efficient Thermal Transport across the Silica-Water Interface

ZH Xu and DZ Huang and TF Luo, JOURNAL OF PHYSICAL CHEMISTRY C, 125, 24115-24125 (2021).

DOI: 10.1021/acs.jpcc.1c06571

In this study, we use nonequilibrium molecular dynamics simulations to study the interfacial thermal transport across the silica-water interface. Using a gold-water interface as a comparison, our results show that the silica-water interface has over 10 times higher interfacial thermal conductance (ITC). Vibrational power spectra (VPS) of the two interfaces indicate that the vibrational coupling at the silica-water interface is stronger, which is an important reason for the high ITC. In addition, our analysis indicates the existence of hydrogen bonds at the silica-water interface, which provides more channels for thermal transport. We further study the hydrogen-bond effect by calculating the ITC of four silica-water interfaces that have different hydroxyl densities. It is found that there are competing effects between different types of hydrogen bonds, and the hydrogen bonds between water and the solid surface can significantly enhance the ITC. In order to evaluate the effect of the vibrational coupling effect, the mass of the water molecules is artificially changed to influence its vibrational properties and thus tune the vibrational coupling effect. By applying sensitivity analysis, it is found that the vibrational coupling effect is a more influential factor. Our results may provide new insights for heat transfer enhancement at hard/soft interfaces.

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