Dynamic birefringence of poly(styrene-4-sulfonate sodium) macromolecules in aqueous solutions at high ionic strengths

For samples of various molecular masses, the flow birefringence of poly(styrene-4-sulfonate sodium) macromolecules in aqueous solutions at various ionic strengths is studied in relation to the concentration of NaCl. It is shown that the sign of birefringence changes from negative to positive with an increase in the ionic strength of a solution. Application of the macroform theory to the Maxwell effect makes it possible to estimate the intrinsic optical anisotropy of the repeating unit of poly(styrene-4-sulfonate sodium) (a||- a⊥) = −17 × 10^-25 cm³), which nearly coincides with similar values known for atactic polystyrene and poly(κ-methylstyrene).