Characterization of lyotropic liquid crystals formed in the mixtures of 1-alkyl-3-methylimidazolium bromide/p-xylene/water

1-Alkyl-3-methylimidazolium bromide (CnmimBr), are substituted for surfactants and formed lyotropic liquid crystalline phases with p-xylene and water. Small angle X-ray scattering (SAXS), polarized optical microscopy (POM), 2H nuclear magnetic response (2H NMR) and rheological measurement were performed to investigate the lyotropic liquid crystalline phases. A lyotropic bicontinuous cubic phase formed in imidazolium-type ionic liquid (IL) system was found for the first time. Moreover, the effect of chain length of CnmimBr on the phase behavior, structural parameters and rheological properties was studied. The strong “π–π stacking” of imidazolium based ILs and their “π-cation” interactions with p-xylene molecules have unique effect on the structural parameters, especially the thickness of the water channel (dW).