An integrated route for purification, cutting and dispersion of single-walled carbon nanotubes

We have developed purification and cutting process of single-walled carbon nanotubes (SWNTs) by integrating (1) an acid reflux treatment to eliminate metal particles, (2) an ultrasonication in the H2SO4/HNO3 and H2SO4/H2O2 to cut and polish the SWNTs, respectively, and (3) an ammonia gas treatment to remove residual carbon impurities and to repair the sidewalls of SWNTs. The final products with a higher purity than 98% are well dispersed in aqueous solution using Pluronic P123 dispersant, which has been rarely used for the SWNTs dispersion. The dispersed SNWTs solution can exist stably for over two months.