Lyotropic liquid crystalline phases formed in ternary mixtures of 1-cetyl-3-methylimidazolium bromide/p-xylene/water: A SAXS, POM, and rheology study

The phase behavior of ternary mixtures of 1-cetyl-3-methylimidazolium bromide (C16mim-Br)/p-xylene/water is studied by small-angle X-ray scattering (SAXS), polarized optical microscopy (POM), and rheology measurements. Two types of lyotropic liquid crystalline phases are formed in the mixtures: hexagonal and lamellar. The structural parameters of the lyotropic liquid crystalline phases are calculated. Greater surfactant content in the sample leads to denser aggregation of the cylindrical units in the hexagonal liquid crystalline phase. The increase in lattice parameter and thickness of the water layer in lamellar phase are attributed to the increase of water content, and the area per surfactant molecule at the hydrophobic/hydrophilic interface for lamellar phase is found to be larger than that for hexagonal phase. The structural parameters of the liquid crystalline phases formed from the cetyltrimethylammonium bromide (CTAB) system are larger than those for the C16mim-Br system. The rheological properties of the samples are also found to be related to the structure of the liquid crystalline phases.

The phase behavior of the ternary mixtures of 1-cetyl-3-methylimidazolium bromide/p-xylene/water is studied by small angle X-ray scattering, polarized optical microscopy and rheology measurements.Figure optionsDownload as PowerPoint slide