Giant cationic polyelectrolytes generated via electrochemical oxidation of single-walled carbon nanotubes

• Published in: Nature communications Vol. 4; no. 1; p. 1989
• Main Authors: Hodge, Stephen A., Bayazit, Mustafa K., Tay, Hui Huang, Shaffer, Milo S. P.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.06.2013; Nature Publishing Group
• Subjects: 639/638/161; 639/925/357/73; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms2989

Previously, reduced single-walled carbon nanotube anions have been used for effective processing and functionalization. Here we report individually separate and distinct (that is, discrete) single-walled carbon nanotube cations, directly generated from a pure anode using a non-aqueous electrochemical technique. Cyclic voltammetry provides evidence for the reversibility of this nanoion electrochemisty, and can be related to the complex electronic density of states of the single-walled carbon nanotubes. Fixed potentiostatic oxidation allows spontaneous dissolution of nanotube cations (‘nanotubium’); Raman spectroscopy and transmission electron microscopy show that sequential fractions are purified, separating amorphous carbon and short, defective single-walled carbon nanotubes, initially. The preparation of nanotubium, in principle, enables a new family of nucleophilic grafting reactions for single-walled carbon nanotubes, exploited here, to assemble nanotubes on amine-modified Si surfaces. Other nanoparticle polyelectrolyte cations may be anticipated. Reduced carbon nanotube anions can be effectively processed and functionalized. Here, the authors prepare discrete nanotube cations by electrochemical oxidation, and the confirmation of their reactivity towards nucleophiles suggests a new library of covalent nanotube modifications.