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Interactions of γ-cyclodextrin (γ-CD) with the single and mixed micelles of sodium dodecyl sulfate (SDS) and sodium lauroyl sarcosine (SLAS) have been studied at different concentrations of γ-CD by using conductivity measurements. From conductivity data, the pure and mixed critical micellar concentration (cmc), the equivalent ionic conductivities of the monomeric species (Λm), the associated species (Λassc) and the micelle (Λmic), the degree of counterion dissociation (χ) in the presence of γ-CD have been evaluated from the slope of the conductivity versus concentration plots for the pure and binary mixture of surfactants. From the dependence of cmc of the surfactantson γ-CD concentration, we have deduced the association constant (K) of surfactant-γ-CD inclusion complexes assuming 2:1 stoichiometry. Theories of Clint, regular solution, and Motomura's have been used for the evaluation of ideality or nonideality of the mixed system. Mixed micelles were found to be rich in SDS content in the presence and the absence of γ-CD. The cmc values have been used to evaluate the transfer of standard free energy of micelles (ΔG0M,tr) from the aqueous medium to additive medium. [ABSTRACT FROM AUTHOR]

In this work, we have studied the influence of different concentrations of β-Cyclodextrin (β-CD) on the mixed micellization of anionic surfactants sodium dodecyl sulfate (SDS) and sodium lauroyl sarcosine (SLAS) at different SDS mole fractions (αSDS). From conductivity data, the critical micellar concentration (cmc), the equivalent ionic conductivities of the monomeric species (Λm), the associated species (Λassc) and the micelle (Λmic), the degree of counterion dissociation (α) in the presence of β-CD were evaluated from the slope of the conductivity versus concentration plots for the pure and binary mixtures. The apparent cmc of the surfactants vary linearly with the β-CD concentrations. From the dependence of cmc of the surfactants on β-CD concentration, we have deduced the association constant (K) of surfactant-β-CD inclusion complexes assuming 1:1 stoichiometry. Theories of Clint, Regular solution, and Motomura's have been used for the evaluation of ideality or nonideality of the mixed system. Mixed micelles were found to be rich in SDS content at the cmc in the presence and the absence of β-CD. The cmc values have been used to evaluate the transfer of standard free energy of micelles (ΔG0M,tr) from the aqueous medium to additive medium. [ABSTRACT FROM AUTHOR]