Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The subject of this study concerns the aggregation process of cationic gemini surfactants with formulas 8 6 8 and 8 12 8. Conductivity measurements carried out within the temperature range of (288.15 323.15) K made it possible to determine the values of critical micelle concentration and dissociation degree of micelles for the system investigated within this temperature range. Using various models, the basic thermodynamic functions (enthalpy, entropy, and free Gibbs energy of micellization) were determined. The data obtained allowed us to assess their usability and the effect of temperature on the micellization process. It has been shown that an increase in temperature causes a linear decrease in the values of ?Hmic and ?Smic, which results from the increase in the repellent interaction force between ammonium groups and increase in the disorder of water structure influencing the hydrophobic effect. Slight changes in the free enthalpy indicate the occurrence of enthalpy entropy compensation. It has been shown that regardless of the model used, the trend of these changes is retained, nevertheless the differences in the values obtained are considerable.