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

Abstract

We present simulations of the basic analytic model of weakly charged polyelectrolytes: monovalently charged monomers with Debye-H\"uckel 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/\ensuremath{\kappa} (${\mathit{L}}_{\mathit{P}}$\ensuremath{\sim}${\mathrm{\ensuremath{\kappa}}}^{\mathrm{\ensuremath{-}}\mathit{y}}$,y1) 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 \ensuremath{\kappa} and the bond length b. \textcopyright{} 1996 The American Physical Society.