Dielectric relaxation and hydrogen bonding interaction in xylitol–water mixtures using time domain reflectometry

Abstract

The measurements of complex dielectric permittivity of xylitol–water mixtures have been carried out in the frequency range of 10 MHz–30 GHz using a time domain reflectometry technique. Measurements have been done at six temperatures from 0 to 25 °C and at different weight fractions of xylitol (0 < W X ≤ 0.7) in water. There are different models to explain the dielectric relaxation behaviour of binary mixtures, such as Debye, Cole–Cole or Cole–Davidson model. We have observed that the dielectric relaxation behaviour of binary mixtures of xylitol–water can be well described by Cole–Davidson model having an asymmetric distribution of relaxation times. The dielectric parameters such as static dielectric constant and relaxation time for the mixtures have been evaluated. The molecular interaction between xylitol and water molecules is discussed using the Kirkwood correlation factor (g eff ) and thermodynamic parameter.