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Order–disorder transitions in poly(3,4-ethylenedioxythiophene)
journal contribution
posted on 2008-01-21, 00:00 authored by B Winther-Jensen, Maria ForsythMaria Forsyth, K West, J Andreasen, Paul Bayley, S Pas, D MacFarlaneThe commonly held perception that high conductivity in conducting polymers is linked to a high level of π-stacking order in the material is shown here to be of lesser importance in highly conducting poly(3,4-ethylenedioxythiophene) (PEDT), which has been prepared by chemical vapour phase polymerisation. Despite the fact that there is a highly energetic phase transition about 130 °C (110 J/g), and that this transition corresponds to a loss of the long-range π-stacking as observed in grazing angle XRD, the conductivity remains unchanged beyond the transition and only decreases by a factor of two when heating to above 200 °C. The XRD data suggest that order in two dimension remains above the phase transition measured by DSC and this order is sufficient to maintain a high level of electronic conductivity. Furthermore, as the ligand on the iron salt used in the synthesis is varied, the conductivity of the PEDT varies over two orders of magnitude. These phenomena cannot be explained by different degree of doping or crystallinity and it is proposed that the iron salt has an ordering effect during the vapour phase polymerisation.
History
Journal
PolymerVolume
49Issue
2Pagination
481 - 487Publisher
Elsevier Ltd.Location
Oxford, EnglandPublisher DOI
ISSN
0032-3861eISSN
1873-2291Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2007, Elsevier Ltd.Usage metrics
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