Universal collapse of the viscosity of supercooled fluids

TL;DR

This paper reveals a universal scaling law for the viscosity of supercooled liquids, showing a collapse of data across 45 different liquids over 16 decades, linking glassy dynamics to melting transitions.

Contribution

It introduces a universal scaling function for supercooled liquid viscosity, unifying diverse liquids under a common behavior and suggesting a fundamental connection to melting transitions.

Findings

Viscosity data for 45 liquids collapse onto a single universal curve.

The scaled viscosity depends on a simple function of temperature difference and melting point.

The behavior is consistent across all known types of supercooled liquids.

Abstract

All liquids in nature can be supercooled to form a glass. Surprisingly, although this phenomenon has been employed for millennia, it still remains ill-understood. Perhaps the most puzzling feature of supercooled liquids is the dramatic increase in their viscosity as the temperature ($T$) is lowered. This precipitous rise has long posed a fundamental theoretical challenge. Numerous approaches currently attempt to explain this phenomenon. When present, data collapse points to an underlying simplicity in various branches of science. In this Letter, we report on a 16 decade data collapse of the viscosity of 45 different liquids of all known types. Specifically, the viscosity of supercooled liquids scaled by their value at their respective equilibrium melting temperature ($\eta(T)/\eta(T_{melt}))$ is, for all temperatures $T<T_{melt}$, a universal function of $(T_{melt} - T)/(B T)$ where $B$ is a constant that does not change significantly from one liquid to another. This exceptionally plain behavior hints at a link between glassy dynamics and the conventional equilibrium melting transition in all known supercooled fluids.