## Phase Equilibria of Polydisperse Square-Well Chain Fluid Confined in Random Porous Media: TPT of Wertheim and Scaled Particle Theory

journal contribution

posted on 15.04.2018, 00:00 by Taras
V. Hvozd, Yurij V. Kalyuzhnyi, Peter T. CummingsExtension
of Wertheim’s thermodynamic perturbation theory
and its combination with scaled particle theory is proposed and applied
to study the liquid–gas phase behavior of polydisperse hard-sphere
square-well chain fluid confined in the random porous media. Thermodynamic
properties of the reference system, represented by the hard-sphere
square-well fluid in the matrix, are calculated using corresponding
extension of the second-order Barker–Henderson perturbation
theory. We study effects of polydispersity and confinement on the
phase behavior of the system. While polydispersity causes increase
of the region of phase coexistence due to the critical temperature
increase, confinement decreases the values of both critical temperature
and critical density making the region of phase coexistence smaller.
This effect is enhanced with the increase of the size ratio of the
fluid and matrix particles. The increase of the average chain length
at fixed values of polydispersity and matrix density shifts the critical
point to a higher temperature and a slightly lower density.