Phase equilibria and plate-fluid interfacial tensions for four-site associating Lennard-Jones fluids confined in slit pores

The excess Helmholtz free energy functional for four-site associating Lennard-Jones (U) fluid was formulated in terms of a modified fundamental measure theory for short-ranged interactions and a first-order mean-spherical approximation theory for long-ranged attraction. Within the framework of density functional theory, the thermodynamic properties including the average density isotherms, density profiles and fractions of not bonded monomers characterizing the coexistences between gas-like and liquid-like phases for capillary condensation, phase equilibria and equilibrium plate-fluid interfacial tensions were investigated. The influences of association energy, fluid-solid interaction and pore width on the inhomogeneous behavior of four-site associating U fluids confined in slit pores were discussed.