Reverse micellisations of nonionic surfactants (Tween 80 and Span 80) in various pure nonaqueous solvents like carbontetrachloride, benzene, toluene, chloroform, cyclohexane and xylene, and in mixed solvent systems like CCl4-DMF and CCl4-DMSO covering the low dielectric range, are studied by UV electronic spectroscopy at 25°C. Micellar aggregation number (ns) in various solvents is evaluated using the hydrophobic dye, Oil Red. 0. The critical micellar concentration (cmc) andns) dependencies on the solvent dielectric, solvent ionization potential, solvent-surfactant interaction potentials, mole fractions of solvents in mixtures and internal pressures are studied. The CCl4-DMSO system shows acmc increase effect, while the CCl4-DMF system shows acmc decrease effect and the excess functions of CCl4-DMSO and CCl4-DMF show increase and decrease effects respectively. Rationalisations of the results and the role of the solvent cage effect have been discussed.
Volume 134, 2022
Continuous Article Publishing mode
Click here for Editorial Note on CAP Mode