Binding of metal ions to polyelectrolytes and their oligomeric counterparts: An application of a generalized Potts model

Competitive binding of metal ions and protons to polyelectrolytes and the corresponding oligomers is studied within a statistical mechanics framework. The problem is formulated with a generalized Potts model, which describes the different states of the macromolecules in terms of appropriate multivalued state variables. The interactions are assumed to be short ranged and can be parametrized in terms of nearest neighbor pair energies. We focus on linear chains, which can be treated with transfer matrix techniques in a straightforward fashion. Binding isotherms for polyelectrolytes and binding constants of different solution complexes are evaluated.