Dielectric relaxation and molecular interaction investigation of glycolic acid-water mixture using time domain reflectometry

Abstract

The complex spectra of glycolic acid (GA) and water mixture have been measured by time domain reflectometry (TDR) in the frequency range 10 MHz to 30 GHz at various temperatures for entire concentration. Dielectric relaxation time (τ), static dielectric constant (ɛ₀) and dielectric permittivity at low frequency (ɛʹ) and at optical frequency (ɛʺ) have been determined from measured complex spectra (ɛ*) using non-linear square fit method. Conductivity, Kirkwood and effective Kirkwood correlation factor of mixture calculated from the determined dielectric parameters have been used to find the alignment of dipoles between molecules. Thermodynamic parameters enthalpy, entropy and Gibb’s free energy have been determined which enable the direction of reaction. Excess permittivity of glycolic acid-water mixture has also been determined which confirms the molecular interaction. Macroscopic parameters such as density and viscosity of mixture have been determined at room temperature. FTIR spectral characterization concedes the solute-solvent interaction.