Swelling and shrinking of polyacid gels

A theory is presented which permits the calculation of discontinuous swelling of polyacid gels in water. The essential new aspect is that acidic groups shall not only dissociate but also form hydrogen bonds among each other yielding additional crosslinks of the polymer network. It is shown that the consideration of this effect is necessary to achieve agreement with experimental results. Additionally, an equation for the osmotic pressure in polyelectrolyte gels is derived. For highly swollen gels this equation reduces to the van't Hoff law for dilute solutions.