The effect of wetting transparency on the interfacial phenomena between water and solid surfaces: an atomistic modeling investigation

Abstract

Experimental and numerical investigations indicate that surface effects govern the transport phenomena in nanoconfined liquids. The wettability of solid surfaces, usually characterized by the static contact angle, has been used to correlate the hydrodynamic boundary condition and the thermal transport at solid-liquid interfaces. Recent investigations suggest the existence of quasiuniversal laws correlating the hydrodynamic slip length and the contact angle in nanoconfined liquid flows. Likewise, a correlation between the work of adhesion and the thermal boundary conductance has been consistently reported in previous investigations. Classical molecular dynamics simulations and a physically sound theoretical background were used to critically assess the effects of wettability on the interfacial momentum and thermal energy transport at solid-liquid interfaces. In particular, the silicon-water interface was investigated due to the rising importance of silicon-based sensors and devices operating in aqueous environments. The wettability of the Si(100) and Si(111) planes was theoretically and numerically characterized. Additionally, the recently discovered wettability transparency phenomenon was considered in this investigation in order to provide a broader perspective of the wettability effects on interfacial transport phenomena. The results indicated that although the wettability of a given surface can be of practical use to describe the hydrodynamic boundary condition and thermal transport in nanoconfined liquids, the interfacial liquid structure properties give a universal description of these phenomena which is being reported here for the first time. These groundbreaking results provide the foundations to theoretically tackle the challenging task of describing interfacial transport in nanoconfined liquids; likewise, these results suggest the possibility of developing highly efficient nanofluidics devices with applications in the biomedical sciences, the energy sector, ultrafast flow delivery systems, low friction nano- and microgap bearings, etc., by means of tailoring the properties of the interfaces in order to achieve low friction flows or highly conductive solid-liquid interfaces.