EFFECT OF TEMPERATURE AND SOLVENT ON THE CRITICAL MICELLE CONCENTRATION OF SODIUM DODECYL-SULFATE

The critical micelle concentration of sodium dodecylsulfate in water-ethanol mixtures has been measured conductometrically as a function of both temperature (in the 10-40-degrees-C range) and of ethanol mole fraction in the water-rich region. The adiabatic compressibility of the plain water-ethanol mixtures in the same concentration and temperature range bas also been determined. The free energy, enthalpy and entropy of micellization have been computed and are related with the possible structure of the solvent system. The present experimental data support the assumption that the dominant mechanism by which ethanol affects the micellization process is through its effect on the structure of water.