ELECTROSTATIC PERSISTENCE LENGTH OF A POLYELECTROLYTE CHAIN

We calculate the electrostatic persistence length l(e) both for flexib le and for stiff polyelectrolytes using a self-consistent variational theory. For the case of intrinsically rigid polyelectrolytes we recove r the classical results due to Odijk, Skolnick, and Fixman (OSF), name ly, l(e) proportional to kappa(-2) where kappa(-1) is the Debye screen ing length. In contrast, l(e) for intrinsically flexible polyelectroly tes is found to be proportional to kappa(-1) in the limit of large scr eening. This is in accord with simulations, experiments, and numerical estimates. We also provide a criterion for the crossover from the OSF result to the behavior observed for intrinsically flexible polyelectr olytes.