Preferential water vapor condensation on a corrugated surface: A molecular dynamics study

Abstract

In this study, we investigate the nucleation and subsequent growth of water clusters on corrugated surfaces using molecular dynamics simulations, with a specific focus on scenarios where the nanostructure sizes are comparable to the critical nucleus size. The primary objective is to reveal the coupled effects of different surface morphologies, i.e., plane, convex, and concave, on water vapor condensation. Regardless of the nanostructures, the condensation process can be divided into two stages, the nucleation stage and the growth stage. It is shown that in the nucleation stage, the concave areas are more conducive to nucleation compared to plane areas, aligning with classical nucleation theory. The total number of condensed molecules is generally proportion to the nucleation ability, while the average size of condensation clusters is affected by the surface nanostructures, with the combination of concave and plane surfaces exhibiting the strongest capability for both water vapor nucleation and cluster growth. Compared to the plane regions, the convex regions not only inhibit nucleation but also block collision and coalescence between clusters. Additionally, increasing the characteristic width of concave and convex structures leads to condensation behaviors approaching those on the plane surface. This indicates that the regulation of the condensation process is feasible by nanostructures within prescribed structural size limits.