2003/11/20 by Yan Levin, Emmanuel Trizac, Lydéric Bocquet +1
Chemistry · Materials Science · Physics and Astronomy · #Electrostatics and Colloid Interactions #Material Dynamics and Properties #Pickering emulsions and particle stabilization #cond-mat.soft #cond-mat.stat-mech
paper · pdf · doi:10.1088/0953-8984/15/48/012
published as J. Phys: Condens. Matt 15, S3523 (2003)
openalex publication_date 2003/11/20 · arxiv created 2004/01/12 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We develop a thermodynamic description of particles held at a fixed surface potential. This system is of particular interest in view of the continuing controversy over the possibility of a fluid-fluid phase separation in aqueous colloidal suspensions with monovalent counterions. The condition of fixed surface potential allows in a natural way to account for the colloidal charge renormalization. In a first approach, we assess the importance of the so called ``volume terms'', and find that in the absence of salt, charge renormalization is sufficient to stabilize suspension against a fluid-fluid phase separation. Presence of salt, on the other hand, is found to lead to an instability. A very strong dependence on the approximations used, however, puts the reality of this phase transition in a serious doubt. To further understand the nature of the instability we next study a Jellium-like approximation, which does not lead to a phase separation and produces a relatively accurate analytical equation of state for a deionized suspensions of highly charged colloidal spheres. A critical analysis of various theories of strongly asymmetric electrolytes is presented to asses their reliability as compared to the Monte Carlo simulations.