Effect of ionic polarization on the static permittivity of electrolyte aqueous solutions

Abstract

AbstractWe developed a theoretical model with two separate components for the description of the static permittivity of aqueous electrolytes versus concentration and temperature. The first component is due to the water molecular polarization, whereas the second component is governed by the ionic polarization. We found that the permittivity part due to the ionic polarization effect is comparable to that come from the water molecule polarization for aqueous electrolytes at ambient temperatures. The microdynamic mechanism of the phenomenon, which the static permittivity of sodium chloride aqueous solution with concentration of 2.8 mol/L holds constant with the change of temperature, is clarified. The equilibrium compensation between the decrement of the permittivity part due to the water molecular polarization and the increase of that originated from the ionic polarization as increasing temperature is responsible for this phenomenon. The dipole moment reduction of water molecules as rising temperature is also confirmed by the model.