Click on a picture for a larger version. In each picture, light blue represents the short chain lipid, and red the long chain lipid.
At high water content, uncharged and undoped smectic lamellae form onion-like, multilamellar vesicles. It is not known whether the vesicle shells are perforated with DHPC pores.
When doped with even a very small amount of charged lipid such as DMPG, smectic lamellar sheets undergo a unbinding transition to spontaneously form unilamellar vesicles at lower concentrations. Like the MLV, it is not known whether the vesicle shells are perforated with DHPC pores.
This is rare example of spontaneous formation of ULV in phospholipid systems.