Percolation, depinning, and avalanches in capillary condensation of   gases in disordered porous solids
  We propose a comprehensive theoretical description of hysteresis in capillary condensation of gases in mesoporous disordered materials. Applying mean-field density functional theory to a coarse-grained lattice-gas model, we show that the morphology of the hysteresis loops is influenced by out-of-equilibrium transitions that are different on filling and on draining. In particular, desorption may be associated to a depinning process and be percolation-like without explicit pore-blocking effects. 
M. L. Rosinberg, E. Kierlik, and G. Tarjus