INTERACTING RIGID POLYELECTROLYTES

A new description of semidilute solutions of rigid polyelectrolyte chains is proposed. The description is based on analytical results obtained for a simple two-dimensional model. These results are then transposed to the physically relevant case of interacting chains in three dimensions. Different behaviours are obtained for salt-free solutions and solutions with added salt. In the latter, the persistence length of a chain is predicted to be only weakly affected by interchain interactions, as postulated by Odijk. In salt free solutions, on the contrary, the persistence length should scale as the interchain distance, which in this case is also the screening length. This behaviour resembles the one predicted earlier by Witten and Pincus. The crossover between these two different regimes, however, is expected to be very sharp, in contrast with their prediction.