Persistence length of weakly charged polyelectrolytes with variable intrinsic stiffness

We present simulations of a basic model of weakly charged polyelectrolyte chains of variable intrinsic stiffness within the Debye-Huckel approximation. Starting from the sublinear dependence of the electrostatic persistence length Le on the screening parameter for flexible chains, the corresponding effective exponent y (Le ~ κ−y) crosses over to values up to 2 when the intrinsic persistence length L0 exceeds the electrostatic one Le. LP shows a pronounced minimum with increasing intrinsic stiffness due to the occurrence of two relevant length scales which influence each other. This makes the concept of a unique persistence length for these systems questionable.