Physico-chemical and dielectric relaxation studies of ionic surfactants in Time Domain Reflectometry (TDR)

Abstract

The properties of aqueous surfactant solutions with external additives are extensively useful in surfactant-based systems. To study the dielectric relaxation studies of aqueous ionic surfactants (SDS, CTAB, DPC) and aqueous butanol, benzyl alcohol, aniline and tributylamine were carried out for different concentrations at 303k. Dielectric relaxation spectroscopy (DRS) is valuable for understanding the dynamic process mainly in micellar systems. Time domain dielectric data were obtained through HP54750A oscilloscope and TDR plug-in-module. The relaxation times were determined through the well-known Cole-Cole method. The superposition of two relaxation times gives the dielectric relaxation time obtained from the hydrated water molecule with rotations around the micelle, ions and another hydrophobic inner side of the micelle. Viscosity measurements were used to correlate the dielectric data. The Kirkwood correlation factor (g f ), effective Kirkwood correlation factor (g eff ), Bruggeman Factor (f B ), excess inverse relaxation time (1/τ) E , excess dielectric constant (e E ) and free energy of activation (ΔF t ) were also calculated. The effects of dielectric relaxation and viscous flow were interpreted and discussed.