Dynamics of micelle-vesicle transitions in aqueous anionic/cationic surfactant mixtures

Abstract

The dynamics of vesicle formation following the rapid mixing of cationic and anionic surfactant solutions, and of their breakup, have been monitored using time-resolved light scattering. Two anionic/cationic surfactant pairs were used in these experiments-sodium octyl sulfate (SOS)/cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS)/dodecyltrimethylammonium bromide (DTAB). The observed temporal variations in scattering intensities over a wide range of surfactant compositions are consistent with vesicle formation being a sequence of a fast process (complete within 4 ms, the 'dead' time in our stopped-flow apparatus), followed by one or more processes which, when analyzed as..