Various bilayer organizations in a single-tail nonionic surfactant: Unilamellar vesicles, multilamellar vesicles, and flat-stacked lamellae

Bilayer structural evolution of a single-tail nonionic surfactant cocodieth anolamide-water system is studied using cryo-transmission electron microsco py (cryo-TEM), small-angle X-ray scattering, light scattering, and rheologi cal measurements. It is found that, with increasing surfactant concentratio n, unilamellar vesicles turn to multilamellar vesicles while at higher conc entrations a fully expressed lamellar phase is clearly observed in the TEM micrographs. The results will be discussed in terms of surfactant geometry and membrane flexibility.