Surfactant micelle characterization using dynamic light scattering

At low concentrations, surfactant molecules are unassociated monomers. As the concentration of surfactant is increased, the attractive and repulsive forces between the molecules cause self-aggregation to occur resulting in the formation of monolayers or micelles (Figure 1). The concentration at which these micelles form is called the critical micelle concentration (cmc). The characteristics of micelles can be controlled by small changes in the chemical structure of the surfactant molecules or by varying the conditions of the disperse phase. Changes in the pH, ionic strength and temperature are all known to influence the size and shape of surfactant micelles. For some cases, the micelle size can be affected by the concentration of surfactant.