Effect of nano-particles on the rheological properties of Reline

Abstract

The emerging utilization of ionic liquid analogues in different separation and chemical applications urges a thorough understanding of their rheological properties. In this study, the rheological properties of Reline as an example of deep eutectic solvents are considered under the effects of varying shear rate, temperature and the existence of solid nanoparticles. Three different common choline chloride:urea molar ratios are considered. In its pure state, Reline is a Newtonian fluid with common rheological properties at near room temperature conditions. The addition of nanoparticles (Aerosil and Laponite) considerably affects the rheological behavior of these fluids. It is interesting to report that the variations of the dispersion properties depend on the concentration of the nanoparticles. It is noticed that at low particle concentrations, the hydrogen bonding and possible electrostatic or van der Waals interactions are dominant, resulting in the increase of the dispersion viscosity. However, the opposite effect of particle–particle interaction becomes dominant at high concentrations and the viscosity of the solution reduces significantly. The effect due to the presence of nano-particles can be utilized to control the flow characteristics of these fluids.