Estel D. Sprague

The effect of a terminal double bond on the micellization of a simple ionic surfactant

Abstract Conductance measurements have been employed to determine the critical micellization concentration (CMC) of sodium 10-undecenoate from 5 to 30°C and of sodium undecanoate from 10 to 30°C. The CMC for sodium 10-undecenoate was found to be about a factor of 2 greater than that for sodium undecanoate from 10 to 30°C, although this factor exhibited a small, but consistent, increase with increasing temperature.

Aggregation of Sodium Undecanoate and Sodium 10-Undecenoate in Water at 37°C: Vapor Pressure Osmometry

Abstract Osmotic coefficients (φ) for aqueous solutions of sodium undecanoate and sodium 10-undecenoate have been determined as a function of surfactant molality (m) at 37°C by vapor pressure osmometry. Plots of φ · m vs m show well-defined breaks yielding critical micelle concentrations of 0.0527 ± 0.0011 and 0.094 ± 0.05 mole/kg, respectively. Burchfield and Woolleys model for the thermodynamics of ionic surfactant solutions (J. Phys. Chem. 88, 2149, 1984) has been shown to give an unbiased description of the experimental data and to yield aggregation numbers of 18 ± 5 (undecanoate) and 12 ± 5 (10-undecenoate).