Studies of Surfactant/Water Systems Near the Critical Micellar concentration Using Thermal Leos Spectroscopy

Abstract

A novel application of photothermal spectroscopy to the study of surfactant-water systems near the critical micellar concentration is reported. The thermal lens signal was induced by a slightly soluble dye and was measured with a dual-beam tllermallens spectrometer. For tlle two surfactants considered: nonyl phenol and Triton X -100, sharp variations of the thermallens signal were observed at tlle critical micellar concentration (CMC), namely an increase for nonyl phenol and a decrease for triton X-100. These effects are arguably related to micelle formation. Our work serves as an initial assessment of the potential of tlle technique for tlle study of disperse systems of a higher complexity or dark systems where conventional techniques are impossible to apply.