Evaporation of a Liquid Droplet in the Presence of a Nanoparticle

Abstract

Nonequilibrium molecular dynamics (MD) simulations have been performed to understand the evaporation of a liquid droplet in the presence of a solid nanoparticle. The influence of solid–liquid interaction strength (εsl) on the evaporation properties was addressed. The system consists of a solid nanoparticle (platinum) engulfed in a droplet (argon) in Argon vapor environment. After the equilibration of this nanoparticle embedded droplet with its vapor, the boundary of this system is heated continuously to evaporate the droplet. It is observed that the addition of a nanoparticle to the droplet resulted in a slower evaporation rate when compared to that of a pure droplet. It was found that the evaporation rate of the droplet is decreased with increasing solid–liquid interaction strength (εsl) and those liquid atoms around the solid nanoparticle with higher εsl are able to delay evaporation even at higher temperature owing to its decreased interfacial resistance. In order to analyze further on the vibrational coupling of the solid and liquid atoms, the vibrational density of states (VDOS) of the solid atoms is studied. It is observed that the DOS of the solid atoms exhibited a higher population in the lower frequency range with the highest peak observed for a lower value of εsl. For low values of εsl, we observe a decrease in the overlap between the VDOS of the solid atom and the interfacial liquid atoms. It is observed that for higher values of εsl, the particle is able to retain a structured layer of liquid even at high temperature and also a higher heat input is necessitated to break the interaction strength of the liquid molecules around the solid nanoparticle, which makes it possible in delaying the complete evaporation of the droplet.