A combination of stopped-flow, transmission electron microscopy and dynamic light-scattering techniques has been used to study the kinetics of vesicle formation and breakdown as well as the mechanism of vesicle formation and breakdown in DTAB/SDS aqueous solutions. The results show that the process of vesicle formation can be modeled as a sequence of distinct processes: mixed micelles→flexible stick-shaped aggregates→non-equilibrium vesicles→equilibrium vesicle system, and the evolution of particle dispersion degree appears to be a periodical change of “monodispersity→polydispersity”. In addition, the kinetic analysis shows that the process of vesicle formation lasts for a long time. However, the activation energy of vesicle formation is not too high, which implies that the control procedure of the process is independent of activation energy. In contrast to the process of vesicle formation, vesicle breakup to mixed micelles appears to be a rapid process.

Key words: vesicle, surfactant, stopped-flow method, effective packing parameter