Effects of surface interactions on heterogeneous ice nucleation for a monatomic water model

Abstract

Despite its importance in atmospheric science, much remains unknown about the microscopic mechanism of heterogeneous ice nucleation. In this work, we perform hybrid Monte Carlo simulations of the heterogeneous nucleation of ice on a range of generic surfaces, both flat and structured, in order to probe the underlying factors affecting the nucleation process. The structured surfaces we study comprise one basal plane bilayer of ice with varying lattice parameters and interaction strengths. We show that what determines the propensity for nucleation is not just the surface attraction, but also the orientational ordering imposed on liquid water near a surface. In particular, varying the ratio of the surface's attraction and orientational ordering can change the mechanism by which nucleation occurs: ice can nucleate on the structured surface even when the orientational ordering imposed by the surface is weak, as the water molecules that interact strongly with the surface are themselves a good template for further growth. We also show that lattice matching is important for heterogeneous nucleation on the structured surface we study. We rationalise these brute-force simulation results by explicitly calculating the interfacial free energies of ice and liquid water in contact with the nucleating surface and their variation with surface interaction parameters.

The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity

“…For this interaction strength the molecules essentially face a hard wall which in turn could even hinder nucleation compared to the homogeneous case 33,[76][77][78] . To understand this we must first mention, what happens for the homogeneous bulk case (which we term Homo) and the case of a free standing water slab (called Homo VAC ) with two water-vacuum interfaces.…”

“…The idea of a small lattice mismatch δ being at the heart of the INA efficacy dates back to the forties, when the ice nucleating capabilities of AgI, featuring only δ ≈ 2 % for the basal face, came to light 19,48 . Even though both experiments 7,49 and recent simulations 33,34 have seriously challenged the validity of this concept and most importantly its generality with respect to other materials 39,41 , a small lattice mismatch is still considered as the primary attribute of an efficient INA. In the case of bacterial ice nucleating proteins ice-matching patterns have even been used as an a priori assumption to infer the three dimensional structure of the residues from the DNA sequence describing the protein 50,51 .…”

“…Because of the length scale involved (nm), insights into the nucleation process can be obtained instead from computer simulations. And indeed, in the last few years a handful of computational studies have been successful in simulating heterogeneous ice nucleation [25][26][27][28][29][30][31][32][33][34][35][36][37] . This indicates that the time is now ripe for furthering our understanding of the microscopic factors that make a material a good INA.…”

“…For this adsorption energy the molecules basically face a hard wall which in turn could even hinder nucleation compared to the homogeneous case 33,[76][77][78] . By analyzing the distribution of pre-critical nuclei (see SI, Figure S8) we find that these avoid the neighborhood of the surface for mentioned E ads range.…”

Not all feldspars are equal: a survey of ice nucleating properties across the feldspar group of minerals

“…Hu and Michaelides, 2007;Cox et al, 2012;Reinhardt and Doye, 2014;Zielke et al, 2015;Cox et al, 2015a, b;Fitzner et al, 2015;Pedevilla et al, 2016). To date there has been little overlap between work of this nature and laboratory experiments.…”