Effect of charge separation on methyl orange homologue-ionene interaction.

Abstract

Methyl Orange and Ethyl Orange were used in the study of the effects of charge separation of polyionic amine (ionene) and hydrophobicity of both the dye and ionene on the interaction between the anionic dye and the cationic polymer. The unit structure of x-y ionene was _??_Br-(CH3)2N+(CH2)xN+ (CH3)2(CH2)yBr-_??_. The x-y for seven ionenes used were 3-3, 3-4, 3-6, 3-8, 3-12, 6-6, and 6-12. The amounts of the dye bound to the ionene were determined by means of equilibrium dialysis procedure. One dye molecule was found to occupy one cationic charged site of ionene. The binding occurred due to the positively cooperative electrostatic and hydrophobic interactions. The results were analysed according to the procedure of McGhee and von Hippel. The interaction constants differed widely from one ionene to another ionene. The binding of the dye to the ionene depended strongly on the charge separation and hydrophobicity of both the dye and the ionene. The entropy change of the interaction process suggested strongly that the dye stacked on the polymer.