EFFECT OF CHARGE SEPARATION ON AGGREGATION OF METHYL ORANGE HOMOLOGUES BOUND TO IONENES

The effect of cationic charge separation on the dye aggregation of Methyl Orange (MO) and Ethyl Orange (EO) bound to polyionic amine (ionene) was studied. The unit structure of x-y ionene was [Br-(CH3)2N+(CH2)xN+(CH3)2(CH2)yBr-]. The x-y values of seven ionenes used were 3-3, 3-4, 3-6, 3-8, 3-12, 6-6, and 6-12. The spectrum of the dye bound to ionene was determined by taking diffrence in absorbances between dye solutions inside and outside of the cellophane tube used for equilibrium dialysis procedure. Since the spectra of MO bound to 3-3, 3-8, 3-12, and 6-12 ionenes revealed distinct peak at about 375nm, the dye was supposed to be card-packed like stacking on those ionenes. Since spectrum of MO bound to 6-6 ionene had a broad band centered at 460nm, the dye was suggested to be monomeric. MO on 3-6 and 3-4 ionenes revealed characteristic spectrum for binary mixture of monomeric and stacked MO. The feature of EO spectrum was slightly different from that of MO. The third distinct band at the lowest wavelength was found at about 360nm in the spectra of EO bound to 3-12 ionene. This peak was considered to be due to higher aggregation on 3-12 ionene. The schematic representation of aggregation of MO molecules bound to the surfaces of some ionenes was given.