SAFT equation of state for fluid mixtures of hard chain copolymers

Abstract

We present the SAFT (statistical associating fluid theory) equation of state for mixtures consisting of heteronuclear hard chain molecules using Wertheim's first-order perturbation theory extended to monodisperse mixtures. The reference fluid is a hard sphere mixture. Since only pure fluid simulation results are available, comparisons of theoretical results with molecular dynamics simulation data are made for the compressibility factor of pure hard chain copolymer systems, namely, block, alternate and random copolymers. Our comparisons show a very good performance of the equation of state. The comparisons of our theory with other equations of state for heteronuclear hard chain fluids show that the SAFT equation of state is almost equivalent to the generalized Flory dimer theory, and it represents a significant improvement over the generalized Flory, Chiew-Percus-Yevick and the modified form of Chiew-Percus-Yevick theories.