Transient Electric Birefringence Measurement of the Persistence Length of Sodium Polystyrene Sulfonate

The persistence length Lp of a flexible polyelectrolyte, sodium polystyrene sulfonate, is measured at very low concentration and ionic strength by transient electric birefringence. The data show that the persistence length reaches, at very low ionic strength, a limiting value which depends on the extended chain length L, but is much shorter than L. The results are not in agreement with the available theoretical predictions.