Laccase-Catalyzed Aniline Polymerization on Multiwalled Carbon Nanotubes: the Effect of Surface Carboxyl Groups on Polyaniline Properties

Polyaniline/carboxylated multiwalled carbon-nanotube composites were synthesized with the use of laccase from the fungus Trametes hirsuta as a catalyst of aniline oxidative polymerization. Atmospheric oxygen was an oxidant. Aniline dimer adsorbed on the carbon material surface served as an enhancer of the enzymatic polymerization of aniline. The composites were synthesized in deionized water without any acidic dopant. The structure, morphology, and electrochemical characteristics of the obtained nanocomposite were examined. It has been shown that the carboxylic groups on the surface of multiwalled carbon nanotubes result in the electrochemical activity of polyaniline in solutions with a neutral pH.