A convenient route to modified multiwall carbon nanotubes with liquid crystal molecules via covalent functionalization

A novel nanocomposite of the rod-like liquid crystal (LC) molecules' waist positions anchored on the surface (sidewalls and ends) of multiwall carbon nanotubes (MWNTs) was prepared by using a dissolving metal reduction method for the first time. The MWNTs carbanion complexes of lithium were first synthesized in tetrahydrofuran with an electron transfer from lithium naphthalene radical anion on the surface of MWNTs. Then the novel material (LC-MWNTs) was obtained by treating the carbanion complexes with bromic liquid crystalline aromatic amide compound. The formation of the LC-MWNTs was confirmed by both Raman and FTIR spectroscopies. HRTEM demonstrates that the rod-like LC molecules are anchored on the surface of MWNTs via covalent attachment, with a wrapped thickness approximately 3-4 nm. The loss-weight fraction of the LC layers for the LC-MWNTs can be roughly estimated as 23% by TGA. The experiments of solubility exhibit that the LC-MWNTs forms a stable suspension solution in polar solvents such as dimethylformamide. © 2011 Wiley Periodicals, Inc.