(190a) Molecular Modeling and Simulation for Closed-Loop Liquid-Liquid Immiscibility Behavior of Poly(ethylene oxide) In Aqueous Solution

The proposed force fields for poly(ethylene glycol) (PEG) or poly(ethylene oxide) (PEO) fail to predict the closed-loop liquid-liquid immiscibility diagrams in aqueous solutions. The proposed Step Potential Equilibria and Dynamics (SPEADMD/C) method implements the field biased discontinuous molecular dynamic and monte carlo (FBDMD/MC) technique using the Wertheim theory of hydrogen bonding for water and PEO. A new  model for water has been proposed and the results have been compared to SAFT-VR molecular approach for different molecular weights. For calibration of our force field, various experimental data from macroscopic properties such as density and vapor pressure of glycols and glymes to microscopic properties such as radius of gyration used to obtain a universal transferable approach. Finally, the effect of hydrophobic and hydrophilic interactions on the excess entropy of mixing for PEO/water mixture has been evaluated.