ION/POLYMER INTERACTIONS IN POLYELECTROLYTE GELS

摘要

We report results from experimental studies performed on polyelectrolyte gels to understand the volume transition induced by multivalent cations. Macroscopic osmotic and mechanical measurements are made to determine the effect of ion binding on the elastic and mixing contributions of the network free energy. Small-angle neutron scattering is used to reveal the role of multivalent ions in the organization of the polymer segments. We demonstrate that combination of scattering and osmotic measurements allows us to determine the characteristic size of the structural elements that contribute to the osmotically driven concentration fluctuations, and yields important information on the effect of ions on the structure and thermodynamic properties at both molecular and supermolecular levels.