The Interactions of Co-Solvent, Co-Solute and Amphiphilic Anionic Dye with Aqueous Solutions of Sodium Dodecyl Sulfate

Abstract

Surface and bulk properties of anionic surfactant and sodium dodecyl sulfate (SDS), both in the absence and presence of co-solvent and co-solute, and its interaction with Bromocresol Green (BCG) in aqueous media were investigated, using surface tensiometry, conductometry, and UV-Visible spectroscopy at 303K. The main co-solvent and co-solute used in this work were ethanol and NaCl, respectively. Surface tensiometry and conductometry were used to detect the values of critical micelle concentration (CMC). The effect of ethanol and NaCl on the CMC and free energy of micellization ( ) was also studied. To enhance the scope of the present study, the interaction and solubilization behaviour of an amphiphilic organic dye, BCG, with SDS in aqueous media was also investigated. Simple, as well as differential, UV-Visible spectroscopy was used to study the solublization behavior of dye-surfactant (BCG-SDS) mixed systems. The partition coefficient (Kx) and the free energy of transfer ) of the dye from water to the hydrophobic interior of the micelle was calculated. The binding behavior of BCG in surfactant solution is reflected in terms of micelle-water partition coefficient (Kx). Low Kx value shows that BCG is partitioned weakly from a polar to a non polar environment in the palisade layer of micelle. doi:10.14456/WJST.2015.93

Keywords

• Micellization
• sodium dodecyl sulfate
• dye
• partition coefficient
• solubilization