Functionalization of multi-walled carbon nanotubes by electrografting of polyacrylonitrile

As a result of their unique architecture and remarkable mechanical and electrical properties[1,2] carbon nanotubes (CNTs)[3] have great potential that remains, however, un-exploited because of poor dispersibility in liquids and problems of processability, Major efforts have, therefore, been devoted towards any modification of the CNTs that could improve their handling[4,5] Typically, chemical modification of CNTs is based on severe oxidation processes that often damage the tubes[5] Mild and single-step electrochemical modification of CNTs is a valuable alternative to the oxidative treatment. There are several reports in the scientific literature on the electrochemical functionalization of CNTs by electroreduction of diazonium salts,[6-8] and on the halogenation of MWNTs by electrolysis However, the grafting of polymers instead of low-molecular-weight compounds onto CNTs by an electrochemical process is a possible strategy for dispersing CNTs in polymer matrices and improving the mechanical properties of CNT-based nanocomposites.. For the past few years, we have been interested in the electiografting of insulating polymer films onto cathodic surfaces, for example, nickel and glassy carbon, provided that the potential and solvent are properly selected.[10-15] These films are designated as "grafted films", because they have the unique property of remaining attached to the electrode surface even when they are prepared and kept in a solvent in which the polymer is highly soluble. The extension of this technique to CNTs has been explored with acrylonitrile as monomer. This communication aims at reporting the functionaliza-tion of multi-walled carbon nanotubes (MWNTs) by the electropolymerization of acrylonitrile.