Entanglement Properties of Polyelectrolytes in Salt-Free and Excess-Salt Solutions.

We study the entanglement properties of polyelectrolytes in salt-free and excess-salt solutions, corresponding to rod-like and expanded coil conformations, respectively. While the solvent's ionic strength has a large impact on the conformation of polyelectrolytes, it does not affect its entanglement density and entanglement crossover. This contradicts current models of polymer entanglement and suggests that the density of binary contacts in solution is not affected by the solvent quality. Based on this observation, we work out the reptation dynamics of polyelectrolytes in salt-free solution, which differ appreciably from earlier models.