Thermodynamics and micellar properties of some surface active cobalt(III) metallosurfactants in nonaqueous medium

Abstract

Abstract The critical micelle concentration (CMC) of four kinds of metallosurfactants of the type halogeno(dodecyl/cetylamine)‐bis(ethylenediamine)cobalt(III) has been studied in n ‐alcohol and in formamide at different temperatures by electrical conductivity method. Specific conductivity data (at 293–313 K) served for the evaluation of temperature‐dependent CMC and the thermodynamic parameters such as standard Gibbs free energy changes (ΔG ), enthalpies (ΔH ), and entropies (ΔS ) of micelle formation. CMCs have also been measured as a function of percentage concentration of alcohol added. It is suggested that alcohol addition leads to increase in formamide penetration into micellar interface that depends on the alcohol chain length. The results have been discussed in terms of increased hydrophobic effect (solvophobic interaction), dielectric constant of the medium, and the chain length of the alcohols, the surfactant in the solvent mixture. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 39: 22–31, 2007