Elsevier

Synthetic Metals

Volume 100, Issue 2, 12 April 1999, Pages 237-239
Synthetic Metals

Short communication
Synthesis of non-doped poly(3,4-ethylenedioxythiophene) and its spectroscopic data

https://doi.org/10.1016/S0379-6779(99)00005-3Get rights and content

Abstract

Non-doped poly(3,4-ethylenedioxythiophene) (PEDOTh) has been synthesized by Ni-promoted dehalogenation polymerization of the corresponding dichloro monomer. Its IR, NMR, and XRD data are compared with those of PEDOTh prepared by chemical oxidation polymerization.

Introduction

Among various polythiophenes, poly(3,4-ethylenedioxythiophene) (PEDOTh) has attracted a special attention due to its high stability in a p-doped state andsolubility as a colloidal solution in the p-doped state in aqueous media 1, 2, 3, 4, 5, 6.

Due to the excellent properties, PEDOTh has already found its practical uses 1, 2, 3, 4, 5, 6. The polymer has been prepared by oxidation polymerization of the corresponding monomer in aqueous media and obtained as the doped polymer, e.g.,

In spite of the strong interest in PEDOTh and many reports on the preparation of PEDOTh, only a little analytic data (including instrumental analytical data) have been published about the polymer. One of the reasons for this seems to be due to difficulties for complete dedoping of the p-doped PEDOTh owing to the stabilizing effect of the electron-donating dialkoxy groups for the p-doped state. In order to obtain further information of PEDOTh, we have carried out organometallic dehalogenation polycondensation of 2,5-dichloro-3,4-ethylenedioxythiophene; such polycondensation usually gives undoped neutral polythiophenes 7, 8, 9, 10. This paper will report results of the preparation of neutral PEDOTh and instrumental analytical data of the neutral PEDOTh in comparison with those of PEDOTh synthesized by the oxidative polymerization (Eq. (1)).

Section snippets

Experimental

3,4-Ethylenedioxythiophene was prepared according to the literature method 11, 12. 2,5-Dichloro-3,4-ethylenedioxythiophene was synthesized by chlorination of 3,4-ethylenedioxythiophene with N-chlorosuccinimide (2.2 mol per 1 mol of 3,4-ethylenedioxythiophene) at 0°C in THF. Analytical calculations for C6H4Cl2O2S: C, 34.1; H, 1.9; Cl, 33.6; S, 15.2%. Found: C, 34.5; H, 2.1; Cl, 33.5; S, 14.9%. The organometallic dehalogenation polycondensation of 2,5-dichloro-3,4-ethylenedioxythiophene was

Results and discussion

The following dehalogenation polycondensation give PEDOTh in good yield:.PEDOTh thus obtained contained no chlorine, supporting the occurrence of a smooth polycondensation. However, determination of the molecular weight of the polymer was not possible due to its insolubility in solutions. PEDOTh prepared by Eq. (1)according to the literature method was not soluble, either, although it was reported that the colloidal dispersion of the polymer in aqueous media could be prepared as a mixture with

References (22)

  • F. Jonas et al.

    Synth. Met.

    (1991)
  • F. Jonas et al.

    Electrochim. Acta

    (1994)
  • D.M. deLeeuw et al.

    Synth. Met.

    (1994)
  • Y. Miyazaki et al.

    Synth. Met.

    (1994)
  • A.-C. Chang et al.

    J. Electroanal. Chem.

    (1987)
  • G. Heywang et al.

    Adv. Mater.

    (1992)
  • F. Jonas et al.

    Macromol. Symp.

    (1995)
  • M. Granström et al.

    Adv. Mater.

    (1995)
  • T. Yamamoto et al.

    J. Polym. Sci., Polym. Lett.

    (1980)
  • T. Yamamoto et al.

    Makromol. Chem., Rapid Commun.

    (1985)
  • T. Yamamoto et al.

    Macromolecules

    (1992)
  • Cited by (74)

    • A green and fast method for PEDOT: Photoinduced step-growth polymerization of EDOT

      2023, Reactive and Functional Polymers
      Citation Excerpt :

      Previous studies concerning the electrochemical and transition metal-mediated oxidation of EDOT have resulted in typically low-molecular weight PEDOTs having low thermal stability and low conductivity [39]. In addition to this, transition-metal catalyzed reactions result in non-conductive PEDOTs due to the formation of neutral species [40]. Even though the chemical oxidation of EDOT can give high molecular weight PEDOT with high conductivity, the addition of excess amount of strong oxidizers using large amount of toxic organic solvents is not an environmentally-friendly method.

    • Progress in understanding structure and transport properties of PEDOT-based materials: A critical review

      2020, Progress in Materials Science
      Citation Excerpt :

      In the synthetic routes that will be presented hereinafter, PEDOT is mainly present in its more stable oxidized p-doped form and is hard to de-dope due to the stabilizing effect of the electron donating dialkoxy groups. Regarding the interest to study the neutral PEDOT, Yamamoto et al. carried out polycondensation of 2,5-dichloro-3,4-ethylenedioxythiophene, following a reaction with a Ni(0) reagent, the scheme is presented in Fig. 8 [73]. The dark purple product was however not soluble and therefore not amenable for molecular weight calculations, similarly to other doped PEDOT.

    • Capillary electrophoresis with photodiode array detection of processable poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate aqueous dispersions

      2012, Journal of Chromatography A
      Citation Excerpt :

      Analysis of the dispersions will, however, improve our understanding of the complexes formed and the conductivity behavior of the film. Spectroscopic analyses have been performed, for example NMR and IR, but the results were inconclusive because of the conductance of PEDOT [6]. UV–Vis spectrophotometry provided a spectrum with an absorption maximum at ∼225 nm that corresponds to PSS in its free and PEDOT-complexed forms [7].

    • The synthesis of poly(3,4-ethylenedioxythiophene) micro/nano-spheres by the demulsifying treatment

      2012, Synthetic Metals
      Citation Excerpt :

      The peaks ranging from 2800 to 3000 cm−1 are assigned to the aliphatic C–H stretching mode depending on the long alkyl tail of DBSA. All these features are corresponded to the FTIR spectra reported in the previous literatures [17,18]. The peaks in the spectrum of PEDOT with the demulsifying treatment, however, are much shaper and better defined.

    • Characterization and conversion determination of stable PEDOT latex nanoparticles synthesized by emulsion polymerization

      2011, Polymer
      Citation Excerpt :

      PEDOT was developed by scientists at the laboratories of Bayer AG in the late 1980s [9,10] and it has been widely used in numerous applications such as electrochromics [11], light emitting diodes [12], solar cells [13], antistatic coatings [14,15], and sensors [16,17]. The electro-donating dialkoxy group of EDOT offers the stabilizing effect on lowering its oxidative doping potential, thus resulting in a stable p-doped state and better defined polymer chains [18,19]. Usually, PEDOT can be prepared by oxidative chemical or electrochemical polymerization.

    View all citing articles on Scopus
    View full text