Densities, Viscosities, and Self-Diffusion Coefficients of Sodium Chloride in Mixed Water-Polyethylene Glycol...

Density, viscosity, and self-diffusion coefficients are reported for solutions of sodium chloride in the mixed solvent of water and polyethylene glycol of 200 g·mol^-1 average molar weight (PEG200), covering temperatures from 298.15 to 358.15 K, sodium chloride molalities from 0 to 3 mol·kg^-1, and PEG200 mass fractions from 0 to 0.4. The obtained densities and viscosities of aqueous PEG200 and the self-diffusion coefficients of aqueous sodium chloride solutions are compared to available literature data. Densities are found to be linearly dependent on w _PEG and nearly linearly dependent on temperature and sodium chloride concentration. The temperature dependence of the viscosity shows only minor deviations from the Arrhenius law, while for the self-diffusion of PEG200 as well as water, no deviations from Arrhenius behavior are discernible. The observable trends in the data suggest that PEG as the bulkiest system component interferes with the motional freedom of the system, while sodium chloride does not. Instead, the density data suggest that sodium chloride prefers to interact with water, while water prefers to interact with itself. However, the aggregation of PEG molecules, which could conceivably result from these interaction patterns, is not indicated in the self-diffusion and viscosity data.