Dielectric relaxation in water-dimethylaminoethanol mixtures as a function of composition and temperature

ABSTRACT

Using Time Domain Reflectometry, the complex dielectric spectra over the frequency range 10 MHz to 20 GHz has been measured in the whole composition range at 288 K, 298 K, 308 K and 318 K for the binary mixtures of water and Dimethylaminoethanol. A systematic variation is observed in dielectric constant (ϵ₀) and relaxation time (τ). The excess dielectric constant (ϵ^E), excess inverse relaxation time (1/τ)^E, Kirkwood correlation factor (g), enthalpy of activation (ΔH), entropy of activation (ΔS) and Gibbs free energy of activation (ΔG) have been determined, to confirm the formation of hydrogen bonded homogeneous and heterogeneous cooperative domains, the dynamics of solute-solute interaction and the hindrance to molecular rotation in the hydrogen bonded water-Dimethylaminoethanol system.

KEYWORDS:

• Dielectric relaxation
• hydrogen bonding
• TDR
• thermodynamic parameters
• excess properties
• Kirkwood correlation factor