Phase Behavior of Lennard-Jones Fluids in Slit-like Pores with Walls Modified by Preadsorbed Molecules: A Density Functional Approach

Abstract

We have studied the liquid−vapor coexistence of Lennard-Jones fluids in slit-like pores with the walls modified by preadsorbed molecules in the framework of the density functional approach. During the preadsorption step, the grafting of monomers, trimers, or chains consisting of spherical segments is performed. The model of tangentially bonded spheres is used for chain molecules. It is shown that the presence of grafted species may induce condensation and layering phase transitions. The crossover between evaporation and condensation is also influenced by grafted species. Phase transitions in the adsorbed fluid affect the microscopic structure of grafted chains and can result in the peculiarities of their thermodynamic behavior. The entire calculations are performed by using the semi-grand canonical ensemble.