Effects of di-, tri-, and tetraethylene glycols on the thermodynamic and micellar properties of Triton X-100 in water

Micellar and surface thermodynamic properties of aggregation of Triton X-100 (TX-100) in mixed solvent systems containing di-, tri-, and tetraethylene glycol with water have been investigated by employing surface tension, density, and fluorescence methods. The differences in Gibbs energies of micellization between water and binary solvent mixtures were determined to evaluate the influence of the co-solvent on the micellization process. From the surface tension measurements, the effects of the co-solvent on parameters such as surface excess, minimum area per molecule, and surface pressure indicate that the surface activity of the surfactant decreases with increasing concentration of the glycol co-solvent. Partial specific volumes, obtained from density measurements, indicate that the fraction of solvent molecules interacting with the micelles by hydrogen bonding vary with the type of additive. Fluorescence studies reveal that quenching of the pyrene probe by cetyl pyridinum chloride in TX-100 micelles is accompanied by simultaneous static and dynamic processes.