Optimization of Parameters to Achieve High Yield and Purity Single-Walled Carbon Nanotube by Thermal and Chemical Oxidation and Its Effect on Conductivity.

Single wall carbon nanotubes due to their unique structural and electronic characteristics have revolutionized the field of nanotechnology and are widely used the field of transistors, drug delivery, and nanocomposities. For improved efficiency of these applications, the utilized tubes must of preeminent purity. Here, we report key parameters that are optimized to achieve their highest purity upto 98 wt%, and yield as high as 50 wt% by thermal and chemical oxidation. The as-produced SWCNT were heated in air at 470 °C, for 90 min, and later subjected to chemical oxidation. The chemical oxidation involved the treatment of thermally treated SWCNT with different concentrations of HCl (4N, 6N, 8N) and 30% H₂O₂, for different time periods (4 hr, 6 hr). This method does not cause damage to the walls of the tubes, observing no loss of nanotubes. The sheet resistance of as-produced and purified tubes was measured and the conductivity was calculated.