Wetting behavior of supercooled water droplets impinging on nanostructured graphite surface: A molecular dynamics study

TL;DR

This study uses molecular dynamics simulations to analyze how supercooled water droplets interact with nanostructured graphite surfaces, revealing velocity thresholds and surface features that influence wetting and penetration behavior.

Contribution

It provides new insights into the velocity-dependent wetting and penetration of supercooled water on nanostructured surfaces at the atomistic level.

Findings

Penetration occurs only above a velocity threshold v*

Smaller surface grooves can prevent water penetration

Droplet temperature affects receding time more than velocity or surface structure

Abstract

In this work, we studied the wetting behavior of impinged and stagnant supercooled water nanodroplet at the atomistic scale using molecular dynamics simulations. We show that water droplet represents a retraction behavior from surface groove nanostructure after indicating maximum penetration. There is a threshold for the value of impinging velocity, v*, below which penetration is not observed which depends on size of the surface roughness. This indicates grooves smaller than a certain size can stop water from penetration, considering v~0.5M in practical situations, which is such a useful information for design of nanostructured ice-phobic substrates. The resistance presumably comes from interfacial tension between solid substrate and liquid water droplet. The extent of water penetration significantly depends on droplet impinging velocity and the size of surface roughness, for impinging velocities higher than V*. Our result indicates the dominant role of droplet temperature on time required droplet recede from surface groove structure rather than droplet impinging velocity and the surface groove nanostructure.