Temperature Effect on Adsorption/Desorption Isotherms for a Simple Fluid Confined within Various Nanopores

We report a Grand Canonical Monte Carlo study of the temperature dependence of adsorption/desorption hysteresis for porous matrices having different morphologies and topologies. We aim at gaining some insights on the concept of critical hysteresis temperature, Tcc, defined as the temperature at which the hysteresis loop disappears. Simulated Tcc for cylindrical, ellipsoidal, and constricted pores follow the experimental scaling law established for MCM-41 silica materials. In contrast, Tcc for Vycor samples with a largest pore size ~2.5 nm and 5.0 nm obey a different relationship, in qualitative agreement with experiments.