Raman and FT-IR studies on dye-assisted dispersion and flocculation of single walled carbon nanotubes

Aqueous suspensions of single walled carbon nanotubes (SWCNTs) were prepared with the aid of dye molecules to form thermodynamically stable colloidal systems. By adding sodium chloride electrolyte, SWCNTs flocculated and settled out due to the destabilization of colloidal systems initiated by the increase in ionic strength. The dye molecules were removed by heat treatment at 300 °C for 5 h following washing with water. Raman spectroscopy was used to monitor the whole procedure. The resulting spectra confirm the non-deconstructive dispersion and flocculation of SWCNTs and the complete removal of the dye molecules; Fourier transform infrared spectroscopy also confirms this.