Capillary condensation in disordered porous materials: Hysteresis versus equilibrium behavior - art. no. 055701

We study the interplay between hysteresis and equilibrium behavior in capil lary condensation of fluids in mesoporous disordered materials via a mean-f ield density functional theory of a disordered lattice-gas model. The appro ach reproduces all major features observed experimentally. We show that the simple van der Waals picture of metastability fails due to the appearance of a complex free-energy landscape with a large number of metastable states . In particular, hysteresis can occur both with and without an underlying e quilibrium transition, and thermodynamic consistency is not satisfied along the hysteresis loop.