Molecular simulations of heterogeneous ice nucleation. I. Controlling ice nucleation through surface hydrophilicity

TL;DR

This study uses molecular dynamics simulations to explore how the surface hydrophilicity of nanoparticles influences heterogeneous ice nucleation, revealing an optimal interaction for promoting ice formation and enabling the design of surfaces with enhanced nucleating ability.

Contribution

It provides new insights into the role of surface hydrophilicity in ice nucleation and demonstrates the design of surfaces with improved ice nucleating properties through molecular simulations.

Findings

Surfaces with different hydrophilicity can both inhibit and promote ice formation.

An optimal surface-water interaction exists for maximum ice nucleation.

Designed surfaces show enhanced ice nucleating ability.

Abstract

Ice formation is one of the most common and important processes on earth and almost always occurs at the surface of a material. A basic understanding of how the physicochemical properties of a material's surface affect its ability to form ice has remained elusive. Here, we use molecular dynamics simulations to directly probe heterogeneous ice nucleation at a hexagonal surface of a nanoparticle of varying hydrophilicity. Surprisingly, we find that structurally identical surfaces can both inhibit and promote ice formation and analogous to a chemical catalyst, it is found that an optimal interaction between the surface and the water exists for promoting ice nucleation. We use our microscopic understanding of the mechanism to design a modified surface in silico with enhanced ice nucleating ability.