Effect of Precipitant (Ethanol) Addition on the Conformation of Polysulfonate Sodium in Water

The present work aims to study the effect of precipitant (ethanol) addition on the polyelectroyte conformation dissolved in water. Viscosity measurements are used to study the behavior of polysufonate sodium (PSS) of molar mass, M_w (g/mol) = 1,000,000, in water/ethanol mixture at 298.15 K in dilute and semi-dilute regimes. In fact, the specific viscosity of the prospected solutions and alcohol mixture composition, x_A, and for all the polyelectrolyte concentration range are determined. The overlapping concentration, C^*(x_A) (g/dl), was deduced for the different mixture composition. This quantity decreases by increasing the quantity of ethanol in the mixture. In the dilute concentration regime, the intrinsic viscosity of PSS and the interamolecular interaction parameter were determined according to the Fuoss equation. The obtained results show a decrease of the intrinsic viscosity when ethanol is added. In the semi-dilute regime, the relative viscosity was determined and the Flory exponent was deduced for PSS in the studied water/ethanol mixture showing that the polyelectrolyte takes different conformation.