EFFECTS OF BOLAFORM ELECTROLYTES ON THE INTERACTION BETWEEN A WATER-SOLUBLE POLYMER AND SULFONATED MONOAZO DYES .2. AROMATIC BOLAFORM ELECTROLYTES

The effect of aromatic bolaform electrolytes which contain two quaternized amino groups and two phenyl rings on the interaction between sulphonated monoazo dyes and poly(vinylpyrrolidone) was investigated using visible absorption spectrum measurements. Since the aromatic bolaform electrolytes aggregated in a higher concentration range, the formation of complexes between the dyes and the bolaform electrolytes was investigated in the concentration range where no aggregate was formed. An equation based on the equilibria in the ternary systems containing the dyes, the bolaform electrolytes and poly(vinylpyrrolidone) was used to estimate the first binding constants of the dye/bolaform electrolyte complexes with poly(vinylpyrrolidone); the values were smaller than those of the dyes themselves. The effect of the aromatic bolaform electrolytes on the interaction between the dyes and poly(vinylpyrrolidone) is discussed, as compared with that of aliphatic bolaform electrolytes, by using thermodynamic parameters calculated from the temperature dependence of the first binding constants.