Morphology and electrochemical properties of amphiphilic viologen functionalized multiwalled carbon nanotube hybrids in Langmuir–Blodgett films

Abstract

Amphiphilic viologens were electrostatically adsorbed on the surface of multiwalled carbon nanotubes (MWCNT) to form viologen–MWCNT hybrids, in which the content of viologens was about 5–10% in weight. Although both viologens and MWCNT hardly dispersed in the water-insoluble organic solvents, the as-prepared viologen–MWCNT hybrids were well dispersed in them with a strong long-term stability, the features of which provided a possibility to prepare their insoluble monolayers at the air–water interface. The surface pressure–area isotherms of these hybrids revealed that they could form stable monolayers, which were transferred on the substrate surfaces by the Langmuir–Blodgett (LB) method. Morphologies of the LB films were characterized by using scanning electron microscopy and atomic force microscopy, the images of which revealed the formation of network two- or three-dimensional films of the functionalized MWCNT. Cyclic voltammograms of the LB films revealed one or two couples of one electron transfer process corresponding to the viologen–MWCNT hybrids with the cathodic and anodic potentials closely related to the alkyl chains of the viologens.