Transport, and thermodynamic investigations on sodium polystyrenesulfonate in ethylene glycol–water media

• Sodium polystyrenesulfonate was studied in glycol (EG)–water conductometrically.
• Moderate concentration-dependent condensation of counterions (23% to 37%) was observed.
• Counterion condensation is spontaneous and depends upon EG-content and temperature.
• A considerable amount of the current is transported by the polyions.
• Monomers experience more friction as EG-content increases and temperature decreases.

Polyion–counterion interactions in sodium polystyrenesulfonate dissolved in (ethylene glycol + water) mixed solvent media have been investigated conductometrically with special reference to their variations as functions of polyelectrolyte concentration, relative permittivity and temperature. Manning counterion condensation theory for polyelectrolyte solutions failed to describe the present experimental results. The data have, therefore, been analyzed using a new model for semidilute polyelectrolyte conductivity which takes into account the scaling arguments proposed by Dobrynin et al. The fractions of uncondensed counterions were found to depend on the polyelectrolyte concentration varying from 0.27 to 0.37, within the concentration range investigated here, indicating a strong interaction between counterions and polyion. A considerable fraction of the counterions is shown to migrate in the same direction as the polyions. The results further demonstrate that the monomer units experience more frictional resistance in solutions as the ethylene glycol content of the mixture increases or as the temperature decreases.

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