The different facets of ice have different hydrophilicities: Friction at water / ice-I$_\mathrm{h}$ interfaces

TL;DR

This study investigates how different ice crystal facets exhibit varying hydrophilicities and frictional behaviors at water interfaces, revealing structural features that influence ice-water interactions and surface contact areas.

Contribution

It provides new insights into the structural and dynamic differences among ice facets affecting their hydrophilicity and frictional properties at water interfaces.

Findings

Prismatic facets show lower solid-liquid friction than basal and pyramidal facets.

Ice/water interfacial widths are similar across facets and unaffected by shear rate.

Prismatic facets have reduced effective contact area with water.

Abstract

We present evidence that the prismatic and secondary prism facets of ice-I$_\mathrm{h}$ crystals possess structural features that can reduce the effective hydrophilicity of the ice/water interface. The spreading dynamics of liquid water droplets on ice facets exhibits long-time behavior that differs for the prismatic $\{10\bar{1}0\}$ and secondary prism $\{11\bar{2}0\}$ facets when compared with the basal $\{0001\}$ and pyramidal $\{20\bar{2}1\}$ facets. We also present the results of simulations of solid-liquid friction of the same four crystal facets being drawn through liquid water, and find that the two prismatic facets exhibit roughly half the solid-liquid friction of the basal and pyramidal facets. These simulations provide evidence that the two prismatic faces have a significantly smaller effective surface area in contact with the liquid water. The ice / water interfacial widths for all four crystal facets are similar (using both structural and dynamic measures), and were found to be independent of the shear rate. Additionally, decomposition of orientational time correlation functions show position-dependence for the short- and longer-time decay components close to the interface.