Field theory for charged fluids and colloids
Max-Planck-Institut für Kolloid-
Kantstr. 55, 14513 Teltow, Germany
2 Service de Physique Théorique, CEA-Saclay, 91191 Gif sur Yvette, France
Accepted: 6 January 1999
Charged systems are considered using field theoretic methods which include fluctuations and correlations via a systematic expansion in powers of the local electrostatic potential. At the Gaussian level we recover the classical Debye-Hückel (DH) theory, which is found to exhibit the full hierarchy of multibody correlations determined by pair-distribution functions given by the screened DH potential. Higher-order corrections can lead to attractive pair interactions between similarly charged particles in asymmetric ionic environments. The phase diagram for an ionic fluid shows a critical point of demixing. The critical temperature and critical density exhibit pronounced deviations from DH theory for highly asymmetric ionic systems.
PACS: 82.70.-y – Disperse systems / 61.20.Qg – Structure of associated liquids: electrolytes, molten salts, etc / 82.45.+z – Electrochemistry and electrophoresis
© EDP Sciences, 1999