Determination of Critical Micelle Concentration of Some Surfactants by Three Techniques

The laboratory experiments described in this work present the CMC-determination of some surfactants by following three different methods, which require the use of the very common techniques in physical chemistry laboratories, such as UV-Vis spectroscopy, luminescence spectroscopy, and electrical conductivity.In performing these experiments, the CMC of a surfactant is determined by measuring a change (i) in the UV-Vis spectra of benzoylacetone, (ii) in the fluorescence emission spectra of pyrene monomers, and (iii) in the electrical conductivity of an ionic-surfactant solution, as the concentration of the surfactant increases.The CMC values corresponding to the surfactants sodium dodecyl sulfate, tetradecyl trimethylammonium bromide and polyoxyethylene,9-dodecyl ether determined in this work following the three indicated methods and in the absence and presence of electrolytes and non-electrolytes are reported.