Water nanodroplets freezing and ice crystal formation on subcooled surfaces.

This article investigates the freezing behavior of water nanodroplets on platinum surfaces using molecular dynamics simulations, identifying three distinct freezing modes dependent on surface temperature: direct freezing into a glassy solid below 175 K; transition from a glassy solid to ice crystals between 176 and 195 K; and direct crystallization from liquid water between 196 and 209 K. The study finds that ice nucleation and growth cause a temporary temperature increase (recalescence) of 20–37 K and that the proportion of cubic ice decreases while hexagonal ice increases as temperature rises. It also establishes that ice crystal nucleation requires molecular distances and kinetic energies within specific thresholds, confining heterogeneous nucleation to a defined temperature range. These findings provide microscopic insights into ice crystallization processes relevant to fields such as chemical engineering, cryobiology, and materials science.