Electrochemical functionalization of single wall carbon nanotubes with phosphorus and nitrogen species

Abstract

Single Wall Carbon Nanotubes (SWCNTs) have been successfully functionalized by electrochemical oxidation in presence of 4-aminophenyl phosphonic acid (4-APPA). Electrochemical modification has been performed by cyclic voltammetry using different upper potential limits, producing the incorporation of N and P functionalities on SWCNT through polymerization reactions, although some covalent attachment cannot be discarded. Electrochemical oxidation in presence of CNT produces polymerization of 4-APPA, what has been related to the interaction between monomer and the CNT surface. The voltammograms of the functionalized SWCNT show different well-defined redox processes that are maintained at high pH. Raman spectroscopy shows that the structure of the SWCNT is maintained even at high potentials suggesting that oxidation selectively occurs in the 4-APPA monomer favoring polymer chain growth. The degree of modification of SWCNT can be easily controlled by selecting the electrochemical conditions.