POLYELECTROLYTE BEAD MODEL .1. EQUILIBRIUM

A polyelectrolyte chain is modeled as a string of charged beads each of which is surrounded by a shell of salt solution. Within a shell the electrostatic potential is described by the nonlinear Poisson-Boltzmann equation. In the region outside the set of shells the equation is linearized and the potential behaves as if it originated in a set of effective charges immersed in a Debye-Hückel solvent. The effective charges are examined for rod-like chains in regard to dependence on bead number, on curvature of the rods, and the approach of other rods. Significant changes from straight-rod values occur only for configurations of very high energy. Ancillary calculations are reported for the second osmotic virial coefficient of cylindrical models of DNA fragments. © 1990 American Institute of Physics.