Density, apparent viscosity, electrical conductivity, interfacial tension, and intermolecular interactions of PEG-ZnCl2-EG solution

Abstract

Abstract Herein we report the thermodynamic and transport properties of a polymer-DES solution. The density, apparent viscosity, electrical conductivity, and interfacial tension for the mixtures of poly (ethylene glycol) (PEG)/zinc chloride (ZnCl2)/ethylene glycol (EG) with various compositions were determined experimentally in the temperature range of 303.15 to 343.15 K. The variations of density, apparent viscosity, electrical conductivity, and interfacial tension with the temperature, PEG concentration, molar ratio of ZnCl2 to EG, and PEG molecular weight were analyzed and interpreted with the variations of H-bond, molecular thermal motion, polymer chain “end” effect, and polymer chain entanglement. The results showed that the hydrogen bond effect displayed enhancement with molar ratio of ZnCl2/EG and weakening with temperature, PEG concentration and molecular weight. The polymer chain “end” effect was enhanced with PEG concentration and weakened with PEG molecular weight. The effect of polymer chain entanglement was enhanced with PEG concentration and molecular weight. At low temperatures the Zn2+-EG H-bond was stronger than Zn2+-PEG while the situation became opposite at high temperatures. The correlations of density, apparent viscosity, and electrical conductivity with temperature and correlation of viscosity with density were conducted and the results showed that the activation energy of viscosity Eη showed increase while the activation energy of conductivity Eκ displayed decrease with the molar ratio of ZnCl2/EG and the closed-packed volumes of the PEG/ZnCl2/EG mixtures displayed increases with PEG concentration.