Lyotropic liquid crystalline phases formed in binary mixture of 1-tetradecyl-3-methylimidazolium chloride/ethylammonium nitrate and its application in the dispersion of multi-walled carbon nanotubes

The phase behavior of a surfactant-like ionic liquid 1-tetradecyl-3-methylimidazolium chloride (C14mimCl) in a room-temperature ionic liquid ethylammonium nitrate (EAN) is studied. The lyotropic liquid crystalline (LLC) phases formed in the binary mixture are thoroughly investigated by polarized optical microscopy (POM) and small-angle X-ray scattering (SAXS) measurements, and the temperature effect on the LC phases is also elucidated. Then, a hexagonal (H1) LC phase was used to disperse multi-walled carbon nanotubes (MWCNTs). Both POM images and SAXS patterns indicate that, the dispersion of MWCNTs cannot break the structure of H1 phase. By comparing the rheological properties before and after dispersing, it could be found that the incorporation of MWCNTs has increased the viscosity of H1 phase.