The relationship between specific conductivity and surfactant concentration was used to determine the solution properties of synthesized anionic sesame fatty acid methyl esters sulphonate (SEFAMESO) surfactant and sodium dodecyl sulphate (SDS) standard. The solution properties evaluated included critical micelle concentration (CMC) values, counter-ion binding degree (β) and thermodynamic parameters namely, Gibbs free energy (∆G°_mic), enthalpy (∆H°_mic) and entropy (∆S°_mic) of micellization.

The conductance measurements were carried out at 298.15, 303.15, 313.15 and 323.15 K using a digital conductivity meter and a dipping-type conductivity cell with platinized electrodes. Absolute conductivity values obtained were multiplied by cell constant to obtain specific conductivity. The average specific conductivity values were plotted against surfactant concentration to obtain the CMC. The ratio of the slope of post-micellar region to that of pre-micellar region of specific conductivity against surfactant concentration curves were used to determine β. The CMC data as a function of temperature were used to determine thermodynamic properties (∆G°_mic, ∆H°_mic and ∆S°_mic) of micellization.