Dielectric dispersion study of poly(vinyl pyrrolidone)-polar solvent solutions in the frequency range 20 Hz-1 MHz

Influence of polar solvents environment and polymer concentrations on the electrical properties (complex dielectric constant, ac electrical conductivity, complex electric modulus and complex impedance) of the solutions of poly(vinyl pyrrolidone) (PVP) in polar solvents, namely water, ethyl alcohol, ethylene glycol, diethylene glycol, poly (ethylene glycol), glycerol, dimethyl sulfoxide and dimethyl formamide, have been investigated in the frequency range 20 Hz-1 MHz at 25 degrees C. Comparative analysis of the dielectric dispersion curves confirms that the solvent molecular size and number of its hydroxyl groups, and the solutions viscosity, are the major factors which governs the PVP chain segmental motion. The ionic conduction and electrode polarization phenomena has a dominant influence on the large increase of complex dielectric constant values of the solutions of PVP-polar solvent in the lower frequency region. The values of relaxation times corresponding to these phenomena are also reported.