Dielectric dispersion and thermodynamic behavior of stearic acid binary mixtures with alcohol as co-solvent using time domain reflectometry

Abstract

Dielectric permittivity and relaxation dynamics of binary and ternary mixture of stearic acid on various concentration and their thermodynamic effects are studied. The static dielectric constant (ε0), dielectric permittivity (ε′) and dielectric loss (ε′′) are found by bilinear calibration. The relaxation time (τ), dielectric strength (Δε) and the excess permittivity (εE) are found. The thermodynamic parameters such as enthalpy (ΔH), entropy (ΔS) and Gibb’s free energy (ΔG) are evolved. The significant changes in dielectric parameters are due to the intramolecular and intermolecular interactions in response to the applied frequency. The permittivity spectra of stearic acid–alcohol in the frequency range of 10MHz to 30GHz have been measured using picoseconds Time Domain Reflectometry (TDR). The dielectric parameters (ε0, ε′, ε′′) are found by bilinear calibration method. Influence of temperature in intermolecular interaction and the relaxation process are also studied. The FT-IR spectral analysis reveals that the conformation of functional groups and formation for hydrogen bonding are present in both binary and ternary mixtures of stearic acid.

Keywords

• TDR
• dielectric relaxation
• stearic acid
• thermodynamic parameters
• FT-IR