Heterogeneous ice nucleation controlled by the coupling of surface crystallinity and surface hydrophilicity

TL;DR

This study uses molecular simulations to reveal that the efficiency of heterogeneous ice nucleation on graphitic surfaces depends on the coupling of surface crystallinity and hydrophilicity, with templating effects enhancing nucleation.

Contribution

It demonstrates that surface crystallinity combined with optimal hydrophilicity can template ice formation, providing new insights into the mechanisms of ice nucleation on graphitic surfaces.

Findings

Crystalline graphitic surfaces with suitable hydrophilicity enhance ice nucleation.

The templating effect shifts from the first to the second water layer as hydrophilicity increases.

Oscillating differences in nucleation efficiency between crystalline and amorphous surfaces were observed.

Abstract

The microscopic mechanisms controlling heterogeneous ice nucleation are complex and remain poorly understood. Although good ice nucleators are generally believed to match ice lattice and to bind water, counter examples are often identified. Here we show, by advanced molecular simulations, that the heterogeneous nucleation of ice on graphitic surface is controlled by the coupling of surface crystallinity and surface hydrophilicity. Molecular level analysis reveals that the crystalline graphitic lattice with an appropriate hydrophilicity may indeed template ice basal plane by forming a strained ice layer, thus significantly enhancing its ice nucleation efficiency. Remarkably, the templating effect is found to transit from within the first contact layer of water to the second as the hydrophilicity increases, yielding an oscillating distinction between the crystalline and amorphous graphitic surfaces in their ice nucleation efficiencies. Our study sheds new light on the long-standing question of what constitutes a good ice nucleator.