Thermodynamic and microscopic properties of bis(2-ethylhexyl) sodium sulfosuccinate (AOT)/ethoxylated-2,5,8,11-tetramethyl-6-dodecyne-5,8-diol (Dynol-604) mixed micelles were investigated at 298.15 K by isothermal titration calorimetry, fluorimetry, and dynamic light scattering. Critical micellar concentrations, enthalpy changes upon dilution and micellization, the polarities of the microenvironment, the sizes and aggregation numbers of the micelles, and the excess thermodynamic quantities of the mixed micelles were obtained to deepen the understanding of the synergistic effect in the mixed surfactant systems. (C) 2014 Elsevier B.V. All rights reserved.