Dielectric relaxation studies in water mixtures of dipropylene glycol using a time domain reflectometry technique

摘要

Complex dielectric permittivity of dipropylene glycol (DPG)-water has been studied by time domain reflectometry technique in the frequency range of 10 MHz to 30 GHz. The measurements have been done at temperature 20 °C, 15 °C and 10 °C and at different volume fractions of dipropylene glycol in water. The dielectric relaxation behaviour of binary mixtures of dipropylene glycol-water has been fitted with Cole-Davidson model having an asymmetric distribution of relaxation time. The dielectric parameters such as static dielectric constant, relaxation time and excess dielectric properties for mixture have been reported here. The molecular interaction between dipropylene glycol and water is discussed using Kirkwood correlation factor (emg/emsupeff/sup) and dielectric constant for mixtures. These parameters have been fitted to the Bruggeman mixture formula in the non-linear case.