Polyelectrolyte complexes. III. Binding characteristics of some polydentate anionic azo dyes to polycations with N,N-dimethyl-2-hydroxypropylene ammonium chloride units in the main chain

Formation of the polycation/dye complexes by the interaction between polycations with (N,N-dimethyl-2-hydroxypropylene ammonium chloride) units in the main chain and three anionic dyes with two, three and six sulfonic groups (Crystal Ponceau 6R, Ponceau 4R and Direct Red 80) confirmed the chromotropic properties of these polycations and gave information on the influence of the polycation and the dye structure on the stability of the polycation/dye complex. The interaction between polycations and dyes and the stoichiometry of the polycation/dye complexes were followed by UV-VIS spectrophotometry and viscometry. The presence of the nonpolar side chains in polycation structure did not increase the ability to bind these dyes. The stability of the polycation/dye complexes increased with the increase of the content of quaternary ammonium salt groups in the main chain and with the increase of the sulfonic group number of the dye.