Résumé
Single Wall Carbon Nanotubes (SWNTs) display remarkable anisotropic features (mechanical, optical and conductivity properties). Exploiting them at a macroscopic scale requires both a good dispersion of individual tubes and a control of their orientational order at a large scale. The use of a liquid crystal as a structured solvent for aligning the tubes is attractive and several studies have already examined the dispersion of SWNTs in thermotropic or lyotropic liquid crystals. In this work, we used Disodium Chromoglycate (DSCG), a chromonic liquid crystal (LCLC) to disperse a large SWNT concentration (more than 0.1 %) in an aqueous nematic phase. The doped nematics and their orientation were studied by polarized microscopy, polarized Raman and photoluminescence spectroscopies (from individual semiconducting SWNT only). A quantitative approach [1-3] allowed us to determine accurately the order parameter of the tubes, which was found to be in the range 0.9-1.