Why ice is so slippery

TL;DR

This study combines nanoscale simulations and a frictional heating model to demonstrate that ice's slipperiness primarily results from frictional heating-induced melting, explaining its velocity-dependent friction behavior.

Contribution

It introduces a multiscale approach that links nanoscale friction simulations with macroscopic heating effects to explain ice slipperiness.

Findings

Frictional heating causes contact temperature to approach melting point.

Nanoscale simulations alone overestimate friction without heating effects.

Frictional heating explains velocity-dependent ice slipperiness.

Abstract

The origin of ice's slipperiness has long puzzled scientists. To resolve this question, we simulate ice- glass (amorphous silica) friction at the nanoscale from first principles and upscale to the macroscale using a frictional heating model. We find that nanoscale simulations alone cannot capture the correct velocity dependence of ice friction, resulting in an overestimated coefficient of friction. By properly accounting for frictional heating, we find a strong increase in contact temperature toward the melting point, even under modest motion of 1 millimeter with velocities above 0.1 m/s, yielding excellent agreement with experimental friction data across a wide range of velocities. While the initial formation of a lubricating film on ice may occur without heating, the ultimate slipperiness of ice hinges on frictional heating, as proposed by Bowden and Hughes in 1939, but without incorporating melting.