Statistics of Fluctuating Colloidal Fluid-Fluid Interfaces

TL;DR

This paper measures and analyzes the slow thermal fluctuations of colloidal fluid-fluid interfaces using confocal microscopy, developing a theory that matches experimental data well.

Contribution

It introduces a theoretical framework for interfacial height fluctuations and validates it with experimental measurements in colloidal systems.

Findings

Excellent agreement between theory and experiment.

Thermal interface motions are slow due to low surface tension.

Confocal microscopy effectively captures interface fluctuations.

Abstract

Fluctuations of the interface between coexisting colloidal fluid phases have been measured with confocal microscopy. Due to a very low surface tension, the thermal motions of the interface are so slow, that a record can be made of the positions of the interface. The theory of the interfacial height fluctuations is developed. For a host of correlation functions, the experimental data are compared with the theoretical expressions. The agreement between theory and experiment is remarkably good.