The study of uniaxial-biaxial phase transition of confined hard ellipsoids using density functional theory

TL;DR

This paper investigates the uniaxial-biaxial phase transition of confined hard ellipsoids using density functional theory, revealing phase changes near walls with a simplified orientation model.

Contribution

It demonstrates the occurrence of uniaxial-biaxial phase transitions in confined ellipsoids using a density functional approach with the HNC approximation and ROM.

Findings

Phase transition occurs near a single hard wall.

Phase transition occurs between two hard walls.

Density functional theory captures the phase behavior.

Abstract

The density profiles and corresponding order parameters of the hard ellipsoids confined between two hard walls and also in contact with a single hard wall are studied using the density functional theory. The Hyper-Netted Chain (HNC) approximation is used to write excess grand potential of the system with respect to the bulk value. To simplify the calculations we use restricted orientation model (ROM) for the orientation of ellipsoids to find the density profiles and order parameters. Density functional theory shows that there is a uniaxial-biaxial phase transition near a single hard wall and also between two hard walls for a fluid consisting of uniaxial hard ellipsoidal particles with finite elongation.