Prediction of the swelling behaviour of amphiphilic hydrogels and the determination of average molecular weight between cross-links

Prediction of swelling behaviour of hydrogels containing cationic and anionic moieties, sensitive to pH and ionic strength changes of the swelling medium was investigated. The equations derived for the prediction of the theoretical swelling curves are based on the phantom network theory and the approaches of Peppas et al. For all predictions, a number of polymer based parameters, solution property parameters and polymer–solvent combination type parameters were evaluated typical of amphiphilic copolymers. The advantages of the derived equations for the determinations of average molecular weight between the cross-links, and also polymer–solvent interaction parameter have been exemplified.