Carbon Nanotubes Incorporated within Lyotropic Hexagonal Liquid Crystal Formed in Room-Temperature Ionic Liquids

Abstract

Multiwalled carbon nanotubes (MWCNTs) were evenly dispersed within hexagonal lyotropic liquid crystals (LLCs) formed in room-temperature ionic liquids (RTILs), ethylammonium nitrate (EAN). Characterization and tribological properties of dispersed system were studied in detail. Polarized optical microscopy images combined with small-angle X-ray scattering (SAXS) results indicate that the MWCNTs are well-dispersed and that the introduction of MWCNTs does not destroy the structure of hexagonal LLCs. The increase of d spacing demonstrates the integration of MWCNTs within the cylinders of the hexagonal LLCs. FT-IR and Raman spectra of the MWCNTs-LLC composites show the characteristic absorption peaks and Raman bands of MWCNTs. The tribological properties were explored to greatly extend the applications of MWCNTs-LLC composites in RTILs as lubricating materials. The rheological measurement results indicate that MWCNTs-LLC composites are highly viscoelastic and that the apparent viscosity is enhanced by the presence of the MWCNTs.