title: Oppositely charged colloidal binary mixtures: a colloidal analog of the restricted primitive model.
abstract: The equilibrium phase diagram of a colloidal system composed of 1:1 mixture of positive and negative particles with equal charge is studied by means of Monte Carlo simulations. The system is the colloidal analog of the restricted primitive model (RPM) for ionic fluids. A liquid-gas transition is found in the low-temperature-low-density region, similar to the liquid-gas transition in the RPM. The fluid-crystal transition is also studied, and the liquid phase is shown to be stable in a narrow range of temperatures. In the liquid, the pair distribution function shows alternating layers of particles with opposite sign of charge surrounding every particle. In the vapor phase, clusters of particles are observed, again in agreement with the RPM. However, a decreasing distribution of clusters is obtained, instead of the discrimination between charged and neutral clusters found in the RPM.
authors.affiliation: Group of Complex Fluids Physics, Department of Applied Physics, University of Almeria, 04120, Spain.
authors.forename: José B
authors.initials: JB
authors.lastname: Caballero
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Puertas
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernández-Barbero
authors.forename: F Javier
authors.initials: FJ
authors.lastname: de las Nieves