Effect of temperature-dependent properties on electroosmotic mobility at arbitrary zeta potentials

Abstract

• Electroosmotic mobility and volumetric flow rate as temperature-dependent zeta potential are determined. • Analytical solutions for electric and hydrodynamic fields by assuming temperature-dependent zeta potentials are obtained. • The zeta potential is obtained as a function of the temperature field in the electroosmotic flow . • Non-isothermal electroosmotic flow at arbitrary zeta potentials is theoretically analyzed. A theoretical analysis to determine the electroosmotic mobility in an electroosmotic flow (EOF) in a microchannel at arbitrary zeta potentials is conducted in this study. As an important characteristic in this work, we consider that the wall zeta potentials of the microchannel and the viscosity and electrical conductivity of the electrolyte solution vary with temperature. The flow and the electric and temperature fields are obtained using lubrication approximation theory (LAT) together with the application of the regular perturbation technique. The electroosmotic mobility is evaluated, showing an increase higher than 18% (for the values of the physical properties used in this work) when physical properties, including the zeta potential of the microchannel walls, are considered as temperature-dependent functions compared with the isothermal case. Additionally, we show that the volumetric flow rate is drastically influenced when the zeta potential varies with temperature.