Freeze-fracture electron microscopy study of mesophases in mixtures of polyoxyethylene (14) oleylether and water

Mixtures of polyoxyethyleneoleylether, with an average of 14 oxyethylene units per molecule, and water, were investigated at between 20‡ and 100‡C using polarization microscopy. A lamellar (Lα), hexagonal (H1), viscous isotropic (V1) and cubic (I1) mesophase were found and an outline of the pseudo binary phase diagram was constructed. The mesophases were investigated with freeze-fracture electron microscopy and micrographs of characteristic textures are presented.Lα andH1 displayed well known features, the repeat distances observed were in good agreement with findings from X-ray diffraction.H1 showed fracture planes with and without a ribbed pattern. Using specific decoration with ice crystals, fracture planes with the ribbed pattern were found to be more hydrophilic.V1 showed regular patterns, in some places forming a square lattice, in other places resembling a network of short rods with two-dimensional hexagonal symmetry. The repeat spacing observed in the textures was about 11 nm.I1 showed foremost fractured layers with a fine texture of spherical units in a two-dimensional hexagonal array. The centre-to-centre distance between these units was about 8–9 nm.