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Correlated conformation and charge transport in multiwall carbon nanotube-conducting polymer nanocomposites

Choudhury, Paramita Kar and Ramaprabhu, S and Ramesh, KP and Menon, Reghu (2011) Correlated conformation and charge transport in multiwall carbon nanotube-conducting polymer nanocomposites. In: Journal of Physics: Condensed Matter, 23 (26).

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Official URL: http://iopscience.iop.org/0953-8984/23/26/265303/

Abstract

The strikingly different charge transport behaviours in nanocomposites of multiwall carbon nanotubes (MWNTs) and conducting polymer polyethylenedioxythiophene-polystyrene-sulfonic-acid (PEDOT-PSS) at low temperatures are explained by probing their conformational properties using small-angle x-ray scattering (SAXS). The SAXS studies indicate the assembly of elongated PEDOT-PSS globules on the walls of nanotubes, coating them partially, thereby limiting the interaction between the nanotubes in the polymer matrix. This results in a charge transport governed mainly by small polarons in the conducting polymer despite the presence of metallic MWNTs. At T > 4 K, hopping of the charge carriers following one-dimensional variable range hopping is evident which also gives rise to a positive magnetoresistance (MR) with an enhanced localization length (similar to 5 nm) due to the presence of MWNTs. However, at T < 4 K, the observation of an unconventional positive temperature coefficient of resistivity is attributed to small polaron tunnelling. The exceptionally large negative MR observed in this temperature regime is conjectured to be due to the presence of quasi-1D MWNTs that can aid in lowering the tunnelling barrier across the nanotube-polymer boundary resulting in large delocalization.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to IOP Publishing ltd.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Id for Latest eprints
Date Deposited: 05 Jul 2011 10:13
Last Modified: 05 Jul 2011 10:13
URI: http://eprints.iisc.ac.in/id/eprint/38878

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