Liquid-glass transition in charge-stabilized colloidal dispersions

We model the inter-colloidal interactions in a charge-stabilized colloidal dispersion by a hard-core Yukawa potential phi(r)=sigma(0)gamma exp(-kr)/r, r> sigma(0) and apply the rescaled mean spherical approximation to calculate its static structure factor. In conjunction with the idealized mode-coupling theory, we determine the loci of the liquid-glass transition phase boundary for a salt-free suspension of charged colloids evaluated at different counter-ion environment (characterized by the k) in terms of the macro-ion parameters: volume fraction eta, charge Z(0) and size sigma(0). The calculated parametric phase diagrams are quite general since the results, with slight and straightforward modification, can be utilized to study the glass transition in a more realistic colloidal solution such as an aqueous monodisperse suspension of polystyrene charged spheres with an added electrolyte. Confining our discussion, then: to the simplest salt-free colloidal liquids, we extract from our analysis of the calculated liquid-glass transition boundaries some succinct features. Specifically, we show in this work that given a range of interaction divided by=k sigma(0) less than or similar to 3.8, there is a possibility of observing the liquid reversible arrow glass reversible arrow liquid reversible arrow glass (LGLG) re-entrant phenomenon in restrictive regions of the phase diagram eta-sigma(0) or eta-Z(0) for a monodisperse charge-stabilized solution. However, as the ao increases above a critical size, the LGLG re-entrant behavior vanishes. To delve into this re-entrant phenomenon, we compare, for a given divided by, the glassy Debye-Waller factor, static structure factor and their spatial counterparts for two cases-one for lower-Z(0) colloids at a high eta and the other for higher-Z(0) colloids at a lour eta. For the former, the glassification is basically driven by the geometric restriction while that, for the latter, it is mainly induced by the Coulomb force. We conclude from this comparison that under the same screening environment both the excluded volume and the electrostatic effects are equally effective in impelling a charge-stabilized colloidal dispersion to undergo a structural arrest configuration and hence the liquid-glass transition.