Structure of poly(ethylene glycol)-water mixture studied by polymer reference interaction site model theory

In this work, the polymer reference interaction site model is applied to investigate the structure of poly(ethylene glycol) (PEG) aqueous solution with the strong hydrogen-bond interactions. In the theoretical model, the renormalized technique of electrostatic potentials is combined with our recently proposed multisite semiflexible chain model to describe the inter- and intramolecular correlations. To test the model for the description of hydrogen bonding, the intermolecular correlation functions of water, ethylene glycol (EG), and EG-water binary mixture are calculated. The results are in good agreement with the corresponding simulation or experimental data. The validated model is then employed to predict the intermolecular correlation functions of different sites of the PEG and its aqueous solution. Another priority of the model is that it can obtain the corresponding direct correlation functions directly.