A model colloidal fluid with competing interactions: bulk and interfacial properties

Abstract

Using a simple mean-field density functional theory theory (DFT), we investigate the structure and phase behaviour of a model colloidal fluid composed of particles interacting via a pair potential which has a hard core of diameter $\sigma$, is attractive Yukawa at intermediate separations and repulsive Yukawa at large separations. We analyse the form of the asymptotic decay of the bulk fluid correlation functions, comparing results from our DFT with those from the self consistent Ornstein-Zernike approximation (SCOZA). In both theories we find rich crossover behaviour, 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 we find, within the DFT, a $\lambda$-line at which the fluid becomes unstable with respect to periodic density fluctuations. SCOZA fails to yield solutions for state points near such a $\lambda$-line. The propensity to clustering of particles, which is reflected by the presence of a long wavelength $\gg \sigma$, slowly decaying oscillatory pair correlation function, and a structure factor that exhibits a very sharp maximum at small but non zero wavenumbers, is enhanced in states near the $\lambda$-line. We present density profiles for the planar liquid-gas interface and for fluids adsorbed at a planar hard wall. The presence of a nearby $\lambda$-transition gives rise to pronounced long-wavelength oscillations in the one-body densities at both types of interface.

14 pages, 11 figures

References in corpus (13)

• Equilibrium cluster phases and low-density arrested disordered states: The role of short-range attraction and long-range repulsion
• Dynamical Arrest in Attractive Colloids: The Effect of Long-Range Repulsion
• A cluster mode-coupling approach to weak gelation in attractive colloids
• Avoided Critical Behavior in O(n) Systems
• Inhomogeneous hard-sphere mixtures: Manifestations of structural crossover
• Freezing and correlations in fluids with competing interactions
• Phase behaviour of charged colloidal sphere dispersions with added polymer chains
• Equilibrium cluster formation and gelation
• A liquid state theory that remains successful in the critical region
• Liquid-gas phase behaviour of an argon-like fluid modelled by the hard-core two-Yukawa potential
• Asymptotic decay of pair correlations in a Yukawa fluid
• Pair correlation functions and phase separation in a two component point Yukawa fluid
• Field-theoretic description of ionic crystallization in the restricted primitive model

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