Determination of the acidic sites of purified single-walled carbon nanotubes by acid-base titration

We report the measurement of the acidic sites in three different samples of commercially available full-length purified single-walled carbon nanotubes (SWNTs) - as obtained from CarboLex (CLI), Carbon Solutions (CSI) and Tube s@Rice (TAR) - by simple acid-base titration methods. Titration of the puri fied SWNTs with NaOH and NaHCO3 solutions was used to determine the total p ercentage of acidic sites and carboxylic acid groups, respectively. The tot al percentage of acidic sites in full length purified SWNTs from TAR, CLI a nd CSI are about 1-3%. (C) 2001 Published by Elsevier Science B.V.