Ionic Interactions of Divalent Transition Metal Sulfate in Aqueous PVOH Systems by Viscosity Method

Abstract

Viscosities of divalent transition metal sulfate (MnSO4, CuSO4 and ZnSO4) having concentration ranging from 2x10-2 to 10x10-2 mol dm-3 in aqueous polyvinyl alcohol (PVOH; 0.1 and 0.9 g dL-1) systems were measured at different temperatures from 298 to 318 K with interval of 5 K. The viscosity data were used to evaluate the ion-ion interaction and ion-solvent interactions in terms of A and B coefficients of Jones-Dole equation respectively. The positive value of B coefficient increased with the increase in temperature reveals that salts behave as structure maker in aqueous polyvinyl alcohol systems. With the help of viscosity data the thermodynamic parameters like energy of activation En, free energy change of activation ΔG* and the entropy change of activation ΔS* were also evaluated as a function of salt concentration, solvent composition and temperature.

Keywords: Viscosity, Divalent transition metal sulfate, Polyvinyl alcohol, Thermodynamic parameters