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Model colloidal fluid with competing interactions: bulk and interfacial properties

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posted on 2014-10-08, 13:35 authored by Andrew ArcherAndrew Archer, D. Pini, Robert Evans, L. Reatto
Using a simple mean field density functional theory (DFT), the authors investigate the structure and phase behavior of a model colloidal fluid composed of particles interacting via a pair potential which has a hard core of diameter, is attractive Yukawa at intermediate separations, and is repulsive Yukawa at large separations. The authors analyze the form of the asymptotic decay of the bulk fluid correlation functions, comparing results from DFT with those from the self-consistent Ornstein-Zernike approximation (SCOZA). In both theories the authors find rich crossover behavior, whereby the ultimate decay of correlation functions changes from monotonic to long wavelength damped oscillatory decay on crossing certain lines in the phase diagram or sometimes from oscillatory to oscillatory with a longer wavelength. For some choices of potential parameters the authors find, within the DFT, a λ line at which the fluid becomes unstable with respect to periodic density fluctuations. SCOZA fails to yield solutions for state points near such a λ line. The propensity towards clustering of particles, which is reflected by the presence of a long wavelength () slowly decaying oscillatory pair correlation function, and a structure factor that exhibits a very sharp maximum at small but nonzero wave numbers, is enhanced in states near the λ line. The authors present density profiles for the planar liquid-gas interface and for fluids adsorbed at a planar hard wall. The presence of a nearby λ transition gives rise to pronounced long wavelength oscillations in the one-body density profiles at both types of interface. © 2007 American Institute of Physics.

Funding

One of the authors (A.J.A.) is grateful for the support of EPSRC under Grant No. GR/S28631/01. Two of the authors (D.P and L.R.) acknowledge support from the Marie Curie program of the European Union, Contract No. MRTN-CT2003-504712.

History

School

  • Science

Department

  • Mathematical Sciences

Published in

Journal of Chemical Physics

Volume

126

Issue

1

Citation

ARCHER, A.J. ... et al, 2007. Model colloidal fluid with competing interactions: bulk and interfacial properties. Journal of Chemical Physics, 126 (1), 014104.

Publisher

© American Institute of Physics

Version

  • VoR (Version of Record)

Publication date

2007

Notes

Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Chemical Physics, 2007, 126 (1), 014104 and may be found at: http://dx.doi.org/10.1063/1.2405355

ISSN

0021-9606

Language

  • en

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