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Structural characterization of conducting polypyrrole using 13C cross-polarization/magic-angle spinning solid-state nuclear magnetic resonance spectroscopy

journal contribution
posted on 01.04.1994, 00:00 authored by Maria ForsythMaria Forsyth, V T Truong, M Smith
13C nuclear magnetic resonance (n.m.r.) has been used to study polypyrrole and N-substituted polypyrrole in the solid state. The extent of oxidation appears to be counterion-dependent; in particular, the quinoid structure appears favoured in the films prepared with dodecyl sulfate. Resonances associated with the quinoid unit are lost upon reduction of the polypyrrole film, which supports the idea that the quinoid structure is associated with the oxidized form of polypyrrole. N-substituted polypyrroles have a more distinct resonance at 110 ppm, which is linked to lower degrees of oxidation or charge delocalization in these systems. The decrease in conductivity of polypyrrole upon thermal ageing in air is associated with both the loss of counterion (‘thermal dedoping’) and the decomposition of the quinoid structure in the polymer backbone. There is no indication of carbonyl formation in the solid-state n.m.r. spectra obtained in the present study.

History

Journal

Polymer

Volume

35

Issue

8

Pagination

1593 - 1601

Publisher

Elsevier Ltd.

Location

Oxford, England

ISSN

0032-3861

eISSN

1873-2291

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1994, Butterworth-Heinemann Ltd.