There is great interest in the process of lipid self-assembly, especially the microstructure formed from lipid mixtures. Spontaneous unilamellar vesicles have been reported by Roberts from mixtures of long-chain lecithins and short-chain lecithins. Alone, dipalmitoyi phophatidylcholine (DPPC) forms normal multilamellar phases, a solid Lβ phase up to about 37°C, a Pβ or ripple phase from 37 to 43°C, and a fluid or Lα phase above 43°C. Diheptanoyl phosphatidylcholine (DHPC) by itself generally aggregates as spherical micelles over this temperature range. At temperatures below 40°C the two lipids, DPPC and DHPC, phase separate, leading to the possibility of physical segregation of the two lipid species. As a result of this separation, the DHPC might migrate to the boundaries of the DPPC-rich bilayers where it could stabilize the bilayer edge to allow the formation of bilayer discs, as first described by Fromherz and Rüppel.