Calculation of liquid–liquid equilibrium in polymer electrolyte solutions using PHSC-electrolyte equation of state

In this work, the capability of the Perturbed Hard Sphere Chain (PHSC) equation of state (EOS) in liquid–liquid equilibrium calculations of salt–polyethylene glycol (PEG)–water systems is investigated. In order to present a comprehensive model, association as well as electrostatic contributions have been added to the original PHSC EOS. In this work 47 systems including PEG (with different molecular weights) and various salts have been modeled at different temperatures. Only two adjustable parameters between salt and PEG and between water and PEG have been employed. Good agreement between experimental data and calculation results is observed. Overall average deviation for all of the systems considered is 6.81%. This study shows that the PHSC EOS can be employed for correlation of phase behavior in aqueous two phase systems.