Viscosity and Interfacial Tension of Binary Mixtures of <i>n</i>-Hexadecane with Dissolved Gases Using Surface Light Scattering and Equilibrium Molecular Dynamics Simulations
Tobias Klein, Frances D. Lenahan, Manuel Kerscher, Julius H. Jander, Michael H. Rausch, Thomas M. Koller, Andreas P. Fröba
Abstract
In the present study, the influence of dissolved gases on the viscosity and interfacial tension of n-hexadecane is investigated using surface light scattering (SLS) experiments and equilibrium molecular dynamics (EMD) simulations. In detail, binary mixtures of n-hexadecane with the solutes hydrogen, helium, methane, water, nitrogen, carbon monoxide, and carbon dioxide are studied in the temperature range between (298 and 573) K and for two solute mole fractions up to 0.2. With SLS, the liquid viscosity and interfacial tension of the binary mixtures were accessed with average expanded uncertainties (coverage factor k = 2) of 2.3 and 1.9%, respectively. By comparing the thermophysical properties of the binary mixtures with the ones of pure n-hexadecane, the influence of the dissolved gases is discussed. For the two lightest gases hydrogen and helium as well as for the solute water, only a small influence of the dissolved gas could be found. For the other gases, a decrease of up to 30% is found for both the viscosity and interfacial tension. While the results for the interfacial tension of the binary mixtures from EMD simulations agree well with the results from SLS measurements, the simulations fail to predict the influence of the dissolved gas on the viscosity accurately. Finally, the enrichment of the solute molecules at the vapor–liquid interface analyzed using EMD simulations is linked to the interfacial tension results.