ABSTRACT
When a charged polymer is dissolved or dispersed as a gel (colloid) in aqueous media the concentration of counterions associated with it will always be a sensitive function of the ionic strength of the solution. Use of the Gibbs-Donnan model has led to a capability for accurate anticipation of the chemical reaction paths of linear, weak-acid polyelectrolytes and their crosslinked gel analogs, of linear, fully dissociated polyelectrolytes and their crosslinked gel analogs, of polysaccharides, of proteins, of glasses, of clays, of hydrous oxide colloids and, indeed, of any charged polymeric material present in aqueous media as a gel, a colloid or as an apparently homogeneously dispersed solute. An example that can be used to document the validity of the Gibbs-Donnan approach takes advantage of the special properties of the Linde-A zeolite. The sudden drop in the value of W'p at the lowest molality examined with the Gibbs-Donnan-based approach merits scrutiny.
