Scattering from polyelectrolyte solutions

Abstract

The small-angle scattering from salt-free polyelectrolyte solutions has been studied as a function of the chain concentration along with the effects of added salt on the system. The theory is based on a multicomponent generalisation of the single-contact approximation that gives equal emphasis to both the intrachain correlations of the polyion and the interparticle correlations of all ionic species present in solution. Two models are introduced. One treats the polyions as macroparticles, while the second considers direct monomer correlations. The interparticle correlations are calculated using the restricted primitive model electrolyte familiar from liquid-state physics. Both models are able to reproduce the qualitative features shown by solutions of biopolymers and synthetic polyelectrolytes.