Dielectric properties of binary and ternary mixtures of alcohols: Analysis of H-bonded interaction in complex systems

The heterogeneous H-bonded interactions in mixtures of glass-former liquids, i.e., binary mixtures of ethyl alcohol (EA) with ethylene glycol (EG) and ternary mixtures of equi-molar EA + EG system with glycerol (Gly) have been investigated at 21 concentrations by using precisely measured values of static and high frequency limiting dielectric constants at 25 degrees C. Concentration dependent observed negative values of excess dielectric constant (epsilon(E)) and effective Kirkwood correlation factor (g(eff)) implies the formation of H-bonded complexes between EA and EG molecules which reduces the effective number of dipoles. The EA + EG system forms the strongest complexes corresponding to the molar ratio similar to 1: 1. The observed positive epsilon(E) values of the (EA + EG) + Gly ternary mixtures confirm the increase in number of effective dipoles contributed to the dielectric constant values due to the formation of the ternary complexes. Critical analysis of the experimental results of the EA + EG and the (EA + EG) + Gly mixtures suggest the suitability of epsilon(E) and g(eff) study in order to explain the dipolar ordering mechanism formed during the complexes between the alcohol molecules in their ternary mixtures. (c) 2007 Elsevier B.V. All rights reserved.