Investigation of dielectric relaxation in dipolar liquids from conductivity measurement.

Conductivity (σ_ijk’s) measurement method is proposed to investigate dielectric relaxation in ternary polar–nonpolar mixture of N,N-dimethyl formamide (DMF)(j) with pyridine(k) or acetonitrile(k) dissolved in p-xylene(i) at various weight fractions (w_jk’s) and temperature under different bands (S, C, X and Ku) of microwave field applying Debye’s dielectric model. Ratio of slopes of imaginary σ_ijk″ vs. w_jk with real σ_ijk′ vs. w_jk of complex conductivity σ_ijk* as well as linear slope of σ_ijk″ vs. σ_ijk′ are used to predict τ_jk’s (relaxation time) and µ_jk’s (dipole moments). Various molecular associations are also identified from the meaningful interactions among polar–nonpolar molecules in terms of τ_jk and µ_jk. Molecular dynamics or molecular environment surrounding the polar molecules DMF, pyridine or acetonitrile is extensively studied with the help of estimated thermodynamic energy parameters. The existence of Debye relaxation mechanism in polar–nonpolar mixture is authenticated by the estimated Debye factor. Microwave sensor development is also ascertained from various dielectric parameters like permittivity, conductivity and penetration depth under microwave field. [ABSTRACT FROM AUTHOR]