Transport and thermodynamic properties of sodium carboxymethylcellulose in dimethyl sulfoxide - water mixed solvent media at 298.15, 303.15, 308.15, and 313.15 K

Equivalent conductivity values of solutions of sodium carboxymethylcellulose in dimethyl sulfoxide-water mixed solvent have been evaluated at varying sodium carboxymethylcellulose concentration, solvent composition and temperature. These experimental data corresponding to the semi dilute regime have been analysed on the basis of the dynamic scaling model for polyion chains proposed by Dobrynin et al. The analysis reveals that with the increase in the value of square root of the polyelectrolyte concentration, the fraction of free counterions decreases suggesting that counterion condensation is favoured at higher polyelectrolyte concentration. It was observed that polyions were responsible for transporting the bulk of the current and the polyions were also found to experience increased frictional resistance in solution with increased dimethyl sulfoxide content in the mixed solvent as well as with the decrease in temperature. These results and observations were qualitatively in line with similar studies carried out with different solvent systems but were quantitatively different.