Fluid phase equilibria of triangle-well fluids confined inside slit pores: A transition matrix Monte Carlo simulation study

Abstract

The phase behaviour of triangle-well (TW) fluids confined inside three types of slit pores: slit pores with or without uniform attraction and slit pores with square-well (SW) type pore-fluid interactions is studied using molecular simulations. The TW potential is chosen to model the fluid-fluid interactions as this model provides a good compromise between realism and simplicity. The simple nature of the models enables us to obtain a qualitative understanding of the effects of confinement on the vapour liquid coexistence curves (VLCCs) of the TW fluids with variable well-width. We note the significant differences in the VLCCs of the confined fluid from the bulk phase behaviour; and also the dependence of the VLCCs on the type of slit pore. These differences have been explained on the basis of the plots of local density along the axis perpendicular to the walls of the slit pore.