Electron Microscopy of Mesomorphic Structures of Aqueous Lipid Phases. I. The System Potassium Oleate/Water

Mesomorphic lyotropic phases, including the gel state of a special soap-water system (potassium oleate), have been studied by electron microscopy over the whole concentration range. Pictures obtained are interpreted in terms of known model structures. Hexagonal, lamellar and rectangular phases are demonstrated. Structural parameters of these phases are measured at room temperature and as a function of concentration. Equations are given for calculating transition concentrations from measured values. The investigation shows that in spite of rigorous preparation techniques results generally are in good agreement with those obtained by X-ray diffraction method. This is of interest for interpretation of ultrastructure of biological specimens in terms of structural parameters of naturally occurring lipids.