Surface tension of bulky colloids, capillarity under gravity and the microscopic origin of the Kardar-Parisi-Zhang equation

TL;DR

This paper resolves discrepancies in colloidal surface tension measurements by identifying gravity-dependent contributions, linking microscopic interface structure to the KPZ growth model.

Contribution

It demonstrates how gravity influences colloidal surface tension measurements and derives the microscopic origin of the KPZ equation from interface structure.

Findings

Gravity-dependent correction explains measurement discrepancies

Surface fluctuations reveal interface structure constraints

Microscopic origin of KPZ growth model identified

Abstract

Experimental measurements of the surface tension of colloidal interfaces have long been in conflict with computer simulations. In this work we show that the surface tension of colloids as measured by surface fluctuations picks up a gravity dependent contribution which removes the discrepancy. The presence of this term puts a strong constraint on the structure of the interface which allows one to identify corrections to the fundamental equation of equilibrium capillarity and deduce bottom-up the microscopic origin of a growth model with close relation to the Kardar-Parisi-Zhang equation.