Hydrogels in Poor Solvents: A Molecular Dynamics Study

The equilibrium swelling behavior of a crosslinked polyelectrolyte gel under poor-solvent conditions is examined. To this end, MD simulations of a coarse-grained network model with a diamond-like topology are employed where the counterions are explicitly taken into account. A large range of different parameter combinations in the fraction f of charged monomers of the network, the strength of electrostatic interactions measured via the Bjerrum length l(B), and various strand lengths are studied. The results agree with data on single PE chains, in particular the theoretically predicted pearl necklace conformations can be identified as well as a sausage-like regime in the strong-coupling region.