CRYOGENIC ELECTRON-MICROSCOPY OF MICELLES AND LYOTROPIC LIQUID-CRYSTALS IN SOME POLAR-SOLVENTS

Micelles and lyotropic liquid crystals in the polar solvents glycerol and formamide have been imaged at high resolution by cryo-transmission electron microscopy (cryvo-TEM) of thin frozen samples. Sample films were prepared in a chamber in which temperature and component chemical activities in the surrounding vapor were controlled. The controlled e vaporation of the solvent on the grid, the so-called on-grid processin g technique, was used to prepare the viscous liquid crystal phase. In dilute solutions of cetyltrimethylammonium bromide (CTAB) in glycerol and sodium dodecyl sulfate (SDS) in formamide there were spherical mic elles, while in the concentrated solution of CTAB in glycerol hexagona l liquid crystals formed. These structures resemble closely in appeara nce the corresponding structures in aqueous solution. Electron beam ra diation damage is much more severe in nonaqueous solutions, and the co ntrast is much lower.