Order-disorder transitions in poly(3,4-ethylenedioxythiophene)

Bjorn Winther Jensen, Maria Forsyth, Keld West, Jens Wenzel Andreasen, Paul Bayley, Steven Pas, Douglas R. MacFarlane

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Abstract

The 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.

Original languageEnglish
Pages (from-to)481-487
Number of pages7
JournalPolymer
Volume49
Issue number2
DOIs
Publication statusPublished - 2008 Jan 21
Externally publishedYes

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Keywords

  • DSC
  • PEDT
  • XRD

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics

Cite this

Winther Jensen, B., Forsyth, M., West, K., Andreasen, J. W., Bayley, P., Pas, S., & MacFarlane, D. R. (2008). Order-disorder transitions in poly(3,4-ethylenedioxythiophene). Polymer, 49(2), 481-487. https://doi.org/10.1016/j.polymer.2007.11.055