NaCl nanodroplet on NaCl(100) at the melting point

TL;DR

This study uses molecular dynamics simulations to investigate the wetting behavior of NaCl(100) surfaces at the melting point, providing insights into interface free energies and wetting properties of ionic crystals.

Contribution

It offers a realistic simulation-based analysis of ionic crystal wetting, estimating interface free energies and explaining reduced wetting ability of NaCl melt.

Findings

Simulations reproduce large contact angle of NaCl(100)

Solid-vapor interface free energy is small and comparable to liquid-vapor

Thermodynamic explanation for reduced wetting ability

Abstract

The self-wetting properties of ionic crystal surfaces are studied, using NaCl(100) as a prototype case. The anomalously large contact angle measured long ago by Mutaftschiev is well reproduced by realistic molecular dynamics simulations. Based on these results, and on independent determinations of the liquid-vapor and the solid-vapor interface free energy, an estimate of the solid-liquid interface free energy is extracted. The solid-vapor surface free energy turns out to be small and similar to the liquid-vapor one, providing a direct thermodynamic explanation of the reduced wetting ability of the ionic melt.