Controlling the nanostructure of electrochemically grown nanoporous composites of carbon nanotubes and conducting polymers

Nanoporous composite films of multi-walled carbon nanotubes (MWNTs) and either polypyrrole (PPy) or poly(3-methylthiophene) (P3MeT) were grown using an electrochemical polymerization technique in which the nanotubes and conducting polymer were deposited simultaneously. The concentration and dispersion of MWNTs in the polymerization electrolyte, in addition to any supporting electrolyte used, were found to have a significant effect on the thickness of polymer coated on each MWNT and hence the nanoporosity and MWNT loading in the films produced. It has been shown that in the absence of a supporting electrolyte, increasing the concentration of MWNTs in the polymerization electrolyte decreases the thickness of polymer coated on each MWNT. This relationship made it possible to minimize ionic diffusion distances and improve electrolyte access within the nanoporous MWNT-PPy films produced, thereby increasing their capacitance relative to similarly prepared pure PPy films. (C) 2004 Elsevier Ltd. All rights reserved.