Swelling dynamics of a polyelectrolyte hydrogel in different aqueous media
Résumé
The swelling behaviour of a polyelectrolyte network in different aqueous media-polymer and salt solutions-has been studied by polarized optical microscopy. The physical changes of the hydrogel and the surrounding solution were monitored in time. The results describe the concentration redistribution of the linear polymer molecules around and inside the gel, depending on the chemical nature of the hydrogel. In the case of a polyvalent metal salt solution, an insoluble birefringent compound is formed first on the surface of the gel, then everywhere inside the gel. This chapter shows how optical microscopy can be used for studying highly swelling gels.