8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Tue 611:23-14:00P2.35Dielectric relaxation study of aqueous binary liquidsusing picosecond time domain reflectometryYogesh Joshi 1 and Dr. Ashok Kumbharkhane 21 Lal Bahadur Shastri Mahavidyalaya, Dharmabad, Dist. Nanded, 431809, Dharmabad,India2 School of Physical Sciences, S. R. T. M. University, Nanded, Nanded, IndiaAs liquid is the least understood state of matter, study of molecular interactions in pure liquids andliquid mixtures is a challenging task. H-bonding is complex in the liquid state due to uncertaintyin identifying the particular bonds and the number of molecules involved. The measurement ofdielectric properties over a wide frequency range gives the information regarding the interfacialpolarization, molecular dynamics and relaxation behavior phenomena. The water is the basic hydrogenbonded liquid in all living matter where as glycol ethers are interesting class of solventhaving the oxy (-O-) and hydroxyl (-OH-) group in the same molecule. Presence of both groupsmay form intra and intermolecular hydrogen bonds between -O- and -OH groups of same or differentmolecules. Therefore the dielectric relaxation study of aqueous binary mixtures becomesuseful to explain the intra and intermolecular hydrogen bonding. The complex permittivity spectraof 2-alkoxyethanols and 2(2-alkoxyethoxy)ethanols in pure form as well as with water solutionshave been investigated over the entire concentrations at 25 ◦ C using a picosecond time domain reflectometrytechnique up to 30GHz. The spectra of 2-alkoxyethanols and 2, 2-alkoxyethoxyethanolare fitted to Cole-Davidson (CD) model. The static dielectric constant (ε 0 ), relaxation time (τ), dielectricconstant at high frequency (ε ∞ ) and distribution parameter (β) for entire concentrations aredetermined by using least square fit method. The excess permittivity (ε 0E ) and Kirkwood correlationfactor (g eff ) were determined to obtain the information about molecular interactions in unlikespecies. The Bruggeman factor (f B ) is also determined for these binary mixtures. Bruggeman expressionpredicts linear relationship between f B and volume fraction of water but the experimentalvalues shows a nonlinear behavior, suggests the certain heterogeneous interaction in mixtures.35