Vesicle transformations resulting from curvature tuning in systems with micellar, lamellar, and bicontinuous cubic phases

LCNP, liquid crystalline nanoparticles, are dispersions of liquid crystalline phases in excess solvent, usually water. Vesicles are the ones derived from the lamellar phase, and are characterized by a spontaneous monolayer curvature close to zero, or a surfactant packing parameter close to one. By changing the composition of amphiphile mixtures, the spontaneous curvature may be changed. This results in a change of the phase behavior as well as in the stability and morphology of the dispersed particles. This article reviews such changes mainly for systems based on polar lipid amphiphiles such as lecithins and glycerylmonooleate mixed with surfactants or amphiphilic block copolymers. Perforated vesicles, stomatosomes, are paid particular attention, not because of their importance as LCNP, but simply because they are least well known. As a tribute to Per Ekwall, some cryoTEM micrographs of vesicles from the "holy system," sodium caprylate-decanol-water, are presented. Stomatosomes were not found in that system.