Persistence length of the Debye-Hückel model of weakly charged flexible polyelectrolyte chains

We present simulations of the basic analytic model of weakly charged polyelectrolytes: monovalently charged monomers with Debye-Hückel interaction coupled by harmonic springs. Quantities such as the chain radii, bond lengths, structure factors, persistence lengths, and scaling properties were examined. The persistence length ${\mathit{L}}_{\mathit{P}}$ shows a sublinear dependence on the screening length ${\mathit{r}}_{\mathit{D}}$=1/κ (${\mathit{L}}_{\mathit{P}}$∼${\mathrm{\kappa }}^{\mathrm{-}\mathit{y}}$,y<1) in strong contrast to all known analytical approaches which propose either y=2 or y=1. The observed exponent y varies as a function of κ and the bond length b. © 1996 The American Physical Society.