Nonstoichiometric polyelectrolyte complexes of chitosan soluble in neutral solutions

The technique of preparing nonstoichiometric polyelectrolyte complexes of chitosan soluble in neutral solutions is developed. Chitosan complexes soluble in neutral solutions and meeting the behavioral criteria of water-soluble nonstoichiometric polyelectrolyte complexes are prepared via mixing of strongly acidic solutions of chitosan and polystyrenesulfonate anions taken in a nonequimolar charge-charge ratio and subsequent neutralization of the products by a solution of alkali. Thus, the region of existence of soluble complexes narrows with a decrease in the length of the host polyanion up to its full degeneration in the case of oligomeric anions. The critical concentration of a salt that brings about phase separation decreases with an increase in the relative content of the guest chitosan in a mixture and depends on the ratio of chain lengths of polymer components.