A droplet near the critical point: the divergence of Tolman's length

TL;DR

This paper demonstrates that Tolman's length, a correction to surface tension near critical points, diverges more strongly than previously thought, with divergence amplitude depending on fluid asymmetry, impacting experimental and simulation observations.

Contribution

It introduces a new universal amplitude ratio linking Tolman's length divergence to fluid asymmetry at criticality.

Findings

Tolman's length diverges more strongly near the critical point.

The divergence amplitude depends on phase coexistence asymmetry.

Potential for experimental detection in microcapillaries and simulations.

Abstract

Application of "complete scaling" [Kim et al., Phys. Rev. E 67, 061506 (2003); Anisimov and Wang, Phys. Rev. Lett. 97, 25703 (2006)] to the interfacial behavior of fluids shows that Tolman's length, a curvature correction to the surface tension, diverges at the critical point of fluids much more strongly than is commonly believed. The amplitude of the divergence depends on the degree of asymmetry in fluid phase coexistence. A new universal amplitude ratio, which involves this asymmetry, is introduced. In highly asymmetric fluids and fluid mixtures the Tolman length may become large enough near criticality to be detected in precise experiments with microcapillaries and in simulations.