Spherical particles in small porous sphero-cylindrical systems: phase diagrams and transfer coefficients

The equilibrium and transport characteristics of spherical particles in sphero-cylindrical porous systems were studied in terms of the lattice-gas model. The supramolecular structure of these systems is modeled by segments with a simple regular geometry (cylindrical and spherical) with additional inclusion of the interconnecting areas between different pore segments. Thus, one can model various types of porous systems ranging from zeolite cavities to stackings of long cylindrical sections in new mesoporous materials such as MCM-41 and MCM-49. The distribution of molecules is described in the quasichemical approximation with allowance for intermolecular interactions. The concentration dependences for local self-diffusion and shear viscosity coefficients were calculated. The contributions of the near-wall regions caused by the molecule—wall potential to the general pattern of phase diagrams, the effect of the pore size on the capillary condensation conditions, and the role of the molecular mobility on pore walls were discussed.