Ergodic-nonergodic phase diagram for a concentrated suspension of charge-stabilized colloids: Rescaled mean spherical approximation

S. K. Lai, G. F. Wang

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Abstract

We calculate the static structure factor of a concentrated suspension of charge-stabilized colloids using the mean spherical approximation, and apply the results obtained to determine its dynamical liquid-glass transition phase boundary within the idealized mode-coupling theory. It is found that the mean spherical approximation closure may yield an unphysical pair correlation function at the minimum distance of contact even at a high volume fraction (≳0.2) when the coupling strength of charged colloids has attained certain high values. In addition, we notice that the Debye-Hückel screening constant κ defined parametrically in one component model generally differs from that defined in the primitive model. In other words, for a fixed macroion size, the κ employed in one-component model calculation may be physically unrealistic. Therefore, we rescale the static structure factor and impose the charge neutrality condition to achieve a self-consistent κ value for the one-component model and the primitive model. As a consequence, we are led to a reasonably reliable ergodic-nonergodic transition boundary that is applicable to charged colloids having different size and charge distribution. We confine our study to a monodisperse system and employ the effective screened Coulomb potential of Belloni [J. Chem. Phys. 85, 519 (1986)] and of Derjaguin-Landau-Verwey-Overbeek to describe in parallel the interactions between colloidal particles. Since the screened Coulomb potential can be modeled to describe a wide range of interactions and has a universal dynamical phase transition loci, our present analysis therefore provides a practical means for extensive studies of charged colloidal structures and, within the mode-coupling theory, of the dynamics of very high density colloids.

Original languageEnglish
Pages (from-to)3072-3082
Number of pages11
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume58
Issue number3
DOIs
StatePublished - 1998

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