Persistence length for a PSSNa polyion in semidilute solution as a function of the ionic strength

The persistence length of sodium sulfonated polystyrene (PSSNa) is measured by small angle neutron scattering in the semidilute regime for two polymer concentrations c as a function of the added salt concentration c(5). The results suggest that this persistence length l(p) depends only on c+2c(s). This questions the role of the counterion condensation at the nanometric scale. Moreover, a variation l(p) similar to(c+2c(s))(-1/3) is found l(p) could be simply related to the distance between ions, which is the relevant length for concentrated solutions.