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A study of acid/base treatments of polypyrrole films using 13C n.m.r. spectroscopy
Electrodeposited polypyrrole films prepared with paratoluenesulfonate (pTS), dodecylsulfate (DDS) and perchlorate anions were treated with acidic and basic solutions, and their structure was investigated by 13C solid state n.m.r. spectroscopy. This technique has confirmed that pTS is completely removed from the film in both acidic and basic solutions whilst DDS is only partially removed and tends to decompose upon treatment with H2SO4. The appearance of shoulders at 143 ppm upon treatment with 0.5 M base indicates formation of a quinoid pyrrole structure. Substitution on the β-carbon by OH cannot be confirmed from the present spectra. Stronger base causes a more dramatic change in the polypyrrole backbone with an obvious increase in the electron density on the β-carbons, consistent with the reduction of the carbon backbone. There is no indication of quinoid units in this case. Acid treatments result in considerable broadening of the main 127 ppm polypyrrole peak.
History
Journal
PolymerVolume
36Issue
4Pagination
725 - 730Publisher
Elsevier Ltd.Location
Oxford, EnglandPublisher DOI
ISSN
0032-3861eISSN
1873-2291Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
1995, Elsevier Science Ltd.Usage metrics
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