Scaling in polyelectrolyte networks

Using scaling arguments, the equilibrium swelling behaviour of a cross-linked polyelectrolyte gel has been investigated by means of molecular-dynamics simulations of a coarse-grained model-, a bead-spring defect-free network with diamond-like topology was considered at the theta-point and under good solvent conditions, where the counterions were treated explicitly. A multitude of systems covering the range between strongly and very weakly charged gels with network chains bearing N-m = 39,..., 259 monomers each were examined for both solvent qualities. We compare the resulting structures with mechanical theories describing the swelling behaviour of such systems which, after taking charge renormalization into account, can then be successfully applied to our measured data.