Local size segregation in polydisperse hard sphere fluids

TL;DR

This paper uses Rosenfeld density functional theory to analyze how particle sizes segregate near walls in polydisperse hard sphere fluids, predicting oscillatory segregation patterns and linking them to reversible work in size changes.

Contribution

It introduces a tractable approach to study local size segregation in polydisperse fluids and connects segregation phenomena to thermodynamic work.

Findings

Predicts oscillatory size segregation near walls

Connects segregation to reversible work for size change

Provides a theoretical framework for continuous polydispersity

Abstract

The structure of polydisperse hard sphere fluids, in the presence of a wall, is studied by the Rosenfeld density functional theory. Within this approach, the local excess free energy depends on only four combinations of the full set of density fields. The case of continuous polydispersity thereby becomes tractable. We predict, generically, an oscillatory size segregation close to the wall, and connect this, by a perturbation theory for narrow distributions, with the reversible work for changing the size of one particle in a monodisperse reference fluid.