Solution studies of the emeraldine oxidation state of polyaniline

F. Zuo, R. P. McCall, J. M. Ginder, M. G. Roe, J. M. Leng, A. J. Epstein, G. E. Asturias, S. P. Ermer, A. Ray, A. G. MacDiarmid

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

Optical studies of emeraldine base in solutions show a red shift in both 2eV and 3.8eV absorption peaks compared with the optical absorption for emeraldine films and powders. As for solids, the 2.0eV peak is absent for the salt form. Unlike the salt film, the strong absorption peak is narrow without the free electron absorption tail, suggestive of strong localization of polarons in the solution form. Dilution studies show there is no shift in the absorption peaks with concentration in both emeraldine base and salt, indicating that optical absorption is an intrachain interaction. Temperature dependent UV-VIS spectra show the first thermochromatic effect in a system without side groups that suggests possible ring flipping. Photoinduced optical studies of emeraldine base polymer in solution shows photoinduced absorption peaks at 1.4eV and 3.0eV and photoinduced bleaching at 1.8eV. The photoinduced absorption peak observed at 0.9eV in film is no longer present. Its disappearance implies the importance of interchain interactions for the formation of the electronic state. In contrast, the 1.4eV absorption is from the interchain excitation of polarons.

Original languageEnglish (US)
Pages (from-to)445-450
Number of pages6
JournalSynthetic Metals
Volume29
Issue number1
DOIs
StatePublished - Mar 7 1989
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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