Conductometric study of interaction between dyes and surface active agents

The interaction of anionic surface active agents e.g. sodium decyl sulphate (SDS), sodium dodecyl sulphate (SDDS), sodium tetradecyl sulphate (STDS), sodium hexadecyl sulphate (DHDS) and sodium octadecyl sulphate (DODS) with cationic dyes, methylene blue (MB), crystal violet (CV) acridine orange (AO), rhodamine 6G (Rh 6G) and quinacrine dihydrochloride (QD) has been studied in three regions by conductometric titration. In the first region ion pair association occurs and the species (cationic and anionic) exist in equilibrium with homogeneous solution. In the second region complexation occurs by 1:1 with MB, CV and AO and by 2:1 with QD and Rh 6G forming a heterogeneousphase, separation and equilibration containing free ions and ion-pair. In the third region the micelle formation occurs by the excess of anions in the presence of cations as well as ion-pair formation and separated complex ions that give solubilization of the complex to a homogeneous clear solution.