Spectroscopic and conductometric investigation of mixed micellar-assisted solubilization of Nile blue sulfate

The solubilization of hydrophobic dyes in aqueous environments poses a significant challenge for textiles and printing industries. Different surfactants have been utilized to improve their dispersion in water to address the limited solubility of these dyes. However, none of the individual surfactants has proven to be entirely satisfactory in overcoming this issue. This study investigates Nile blue sulfate (NBS) solubilization using micellar and mixed micellar media of positively and negatively charged amphiphiles like TTAB, CTAB, SDBS, and SDS. UV-visible spectroscopy and conductometry were employed to analyze the solubilization process and understand the interactions between the dye and mixed micelles. The spectroscopic technique provided insights into the formation of dye-micelle complexes, the partition coefficient (Kx), binding constant (Kb), and Gibbs energies of corresponding processes. Conductometric measurements offered valuable information to estimate critical micelle concentration (CMC) and derivation of thermodynamic parameters (& UDelta;Gm, & UDelta;Sm, and & UDelta;Hm) of micellization at different temperatures. The findings from both techniques indicated that micellization and solubilization occurred spontaneously. Additionally, the mixed micelles exhibited different binding and partitioning abilities due to the synergistic effects of cationic and anionic surfactants.