Dielectric Relaxation in Glycine–Water and Glycine–Ethanol–Water Solutions Using Time Domain Reflectometry

Abstract

Dielectric relaxation measurements on water–ethanol–glycine ternary system were carried out using time domain reflectometry (TDR) at 25, 30, 35, and 40°C in the frequency range from 10 MHz to 10 GHz. Glycine–ethanol–water solutions are prepared with different concentrations of ethanol (0, 5, 10, 15, 20, and 30%) and also for different glycine molar concentrations (0, 0.2, 0.4, 0.6, 0.8, and 1 M). The dielectric relaxation parameters are measured for aqueous glycine solutions also to compare the results with those for the glycine–ethanol–water ternary system. For all the mixtures considered, only one relaxation peak was observed in this frequency range. All the mixtures display a Cole–Davidson dispersion. The relaxation peaks shift to lower frequency with an increase in glycine concentration and also with ethanol concentration. The logarithm of the relaxation time log(τ) shows a nonlinear relation with glycine concentration which implies a change of relaxation mechanism with glycine concentration. The dielectric strength Δe for these mixtures shows a nearly linear relation with glycine molar concentration.