Investigating the Rectilinear Law and Critical Exponent for Confined Fluids

The structure and properties of fluids confined in nano-pore may show a dramatic departure from macroscopic bulk fluids. The main reason for this difference is the influence of system walls. In addition to entropic wall effect, system walls can change the energy of the confined fluid significantly as compared with macroscopic bulk fluids. The energy effect of the wall on a nano-confined fluid, appears in two forms. The first effect is the cutting of intermolecular interactions by the walls, which appear for example in the integrals for calculation for the thermodynamic properties [1]. The second wall effect is the wall-molecule interactions. In such confined fluids, the introduction of wall forces and the competition between wall-fluid and fluid-fluid forces could lead to interesting thermodynamic properties, including new kind of phase transitions not observed in the macroscopic fluid systems examples include ‘layering and wetting transitions as well as shifts in regular bulk transitions (e.g., freezing, gas–liquid, and liquid–liquid)[2]. In this study we have investigated some known regularities of bulk fluids in confined fluids.