The density profile of hard sphere fluid confined in two parallel hard walls was studied by using Rosenfeld density Functional Theory (DFT) and Molecular Dynamics (MD) simulation method.

By taking the neutral hard sphere-charged hard sphere mixture as reference fluid, an EOS for density calculation is developed with perturbation theory.

The new associating hard sphere chain equation combined the hard sphere chain model (HSC) of self-diffusion coefficient with the statistical associating fluid theory (SAFT).