Polyelectrolyte complexes of naturally occurring fucoidans with cationically and hydrophobically modified hydroxyethyl cellulose

Polyelectrolyte complexes were formed through the mixing of aqueous solutions of naturally occurring sulfated fucoidans with hydroxyethyl cellulose derivatives containing cationic and hydrophobic substituents. It was shown that the formation of polyelectrolyte complexes is determined by the type and arrangement of substituents and the degree of charging, as well as the composition of polysaccharide molecules. In the case of fucoidans, xylose residues that hamper association with cationic derivatives of hydroxyethyl cellulose were found to exert a strong effect on the process under consideration. As for hydroxyethyl cellulose derivatives, hydrophobic substituents and their location in a molecule play an important role. If a hydrocarbon chain is directly attached to a cationic group, the generation of polyelectrolyte complexes is hampered owing to the loosening of electrostatic interactions as a result of shielding of a charged site.