  The interaction of double wall carbon nanotubes (DWCNTs) and the conducting
polymer poly(3,4-ethylenedioxythiphene/polystyrenesulfonate (PEDOT/PSS) was
studied by in-situ Raman spectroelectrochemistry. The mixing of DWCNTs with
PEDOT/PSS caused a partial doping of the outer tube of DWCNTs, which was
indicated by the relative change of the Raman intensity of the DWCNTs features.
On the other hand, the bands corresponding to inner tubes of DWCNTs and to the
polymer were almost untouched by assembling both species into a composite. The
in situ Raman spectroelectrochemical experiments have shown that the changes in
electronic structure of inner tubes of DWCNTs embedded in PEDOT/PSS matrix are
dependent on the doping level. While at the low doping level of the composite,
the Raman features of inner tubes of DWCNTs do not change significantly, at
high doping level they reflect the changes caused by the applied
electrochemical potential similar to that observed in the polymer-free DWCNTs.
