Conductometric and Spectrophotometric Study of the Interaction of Methyl Violet with Sodium Dodecyl Sulfate

The interactions of cationic dyes (methyl violet) with anionic surfactant sodium dodecyl sulfate (SDS) was studied in process of solubilization. The critical micelle concentration of the SDS with and without dye was determined by spectrophotometry and specific conductometry methods. The binding constant (Kb) and Gibbs free energy (∆Gͦ) were calculated at room temperature. Kb was calculated by means of Benesi-Hildebrand Equation. Results obtained showed that the Kb and ∆ Gͦ are found to be = 432.77 M-1 and -15.03 KJ mol-1, respectively. The value of ∆ Gͦ indicates that the interaction of methyl violet with micelles is spontaneous.