Micelle Formation and Micellar Size by a Light Scattering Technique

The micelle formation and micellar size (diameter) of various surfactants were studied by light scattering. Each critical micelle concentration (cmc) determined from change in the intensity of scattered light with concentration was slightly higher than that based on change in surface tension with concentration. The concentration at which micelles could first be detected in solution by dynamic light scattering was considerably higher than the cmc determined as above. This difference may be due to the ability of light scattering to detect change in monomer or micelle concentration. Micellar size as determined by dynamic light scattering decreased with increasing concentration of surfactant due to intermicellar (micelle-micelle) interactions.