Phase diagram of a symmetric binary fluid in a porous matrix - art. no. 011502

The phase behavior of a binary symmetric fluid in thermal equilibrium with a porous matrix has been studied with the optimized random phase approximat ion and grand canonical Monte Carlo simulations. Depending on the matrix pr operties and the matrix-fluid and fluid-fluid interactions we find three ty pes of phase diagram characterized by a tricritical point, a tricritical po int with a triple point, or a critical end point. Small changes in the prop erties of the matrix or in the interactions are demonstrated to lead to dra stic modifications of the phase diagram of the fluid. in qualitative agreem ent with observations in experimental studies. We show, in particular, that the change between the different types of phase diagram is triggered not o nly by the fluid-fluid interactions (internal parameters) but also by the p roperties of the matrix and of the matrix-fluid potentials (extemal paramet ers).