Role of mixed micellar media to enhance solubilization of Allura Red: differential spectroscopic and conductometric study

The reported work is an attempt to explore the most appropriate micellar media for the solubilization of organic dye, Allura Red (AR). The micellar solution of anionic surfactant i.e. sodium dodecyl sulphate, SDS and mixed micellar solutions of SDS and cetyltrimethylammonium bromide, CTAB (cationic surfactant) have been employed for said purpose. The values of partition coefficient, K _x and Gibbs free energy change of partition, ΔG _p decide the suitable composition of surfactant solution with the highest solubilizing power. The said parameters have been determined from data of UV/Visible spectroscopy while thermodynamic parameters (ΔG _m, ΔH _m and ΔS _m) have been calculated from specific conductivity data. The effect of the presence of various concentrations of CTAB i.e. 0.1, 0.2 and 0.4 mM has been observed to find the most suitable concentration of CTAB that produces a maximum increase in the solubilizing capacity of SDS solution.