Salinity controlled vesicle formation and growth in aqueous mixture of aerosol OT/Triton X-100

Mixed vesicles can be formed spontaneously from aqueous mixture of the double-tailed anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and the nonionic surfactant octyl-phenoxypolyethoxyethanol ( Triton X-100) under the inducement of salt, the formation mechanism of which should be attributed to the compression of salt on the electric bilayers of the head groups. The stability and the polydispersity of the vesicles are superior to single-component AOT vesicles, which can be proved by the TEM image and visual observation. The vesicle region was presented in a pseudo-ternary diagram of AOT/TX-100/brine. The size of the vesicle was measured using dynamic light scattering. It is found that the vesicle size increases with the salinity but decreases with the content of TX-100 in the mixture at the same salinity. Especially, the vesicle size is independent of the surfactant concentration at fixed salinity.