Electrical conductivity of dilute and semidilute aqueous polyelectrolyte solutions. A scaling theory approach

We study the low-frequency electrical conductivity of flexible charged poly mer chains in salt-free aqueous solutions on the basis of the Manning count erion condensation model, taking into account a dynamic scaling description recently proposed by Dobrynin, Colby, and Rubinstein (Macromolecules 1995, 28, 1859) of the polyion configuration in different concentration regimes covering both the dilute and semidilute regions. We compare the prediction of this model with conductivity data obtained for salt-free aqueous solutio ns of poly(L-lysine) of four different molecular weights (from 4 to 167 kD) , over an extended concentration interval to cover the different regimes, f rom dilute to semidilute unentangled solutions. Our predictions are found t o compare favorably well with the observed conductivity behavior over the w hole concentration range investigated.