In situ UV-visible spectroelectrochemical studies on electrochromic behavior of poly(2,5-dimethoxy aniline)

Li Ming Huang, Ten Chin Wen, A. Gopalan

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42 Citations (Scopus)

Abstract

The electrochromic characteristics of poly(2,5-dimethoxy aniline) (PDMA), have been evaluated using cyclic voltammetry, in situ UV-visible (UV-VIS) spectroscopy, cyclic spectrovoltammetry and spectrochronoamperometry. The results from cyclic voltammetry revealed that PDMA could be easily transformed from leucoemeraldine to emeraldine state in comparison with polyaniline (PANI). The conversion of reduced PDMA form into fully oxidized state could occur at a lower positive potential for PDMA than PANI (0.70V for PANI and 0.27V for PDMA). UV-VIS spectrum of PDMA showed three optical transitions at λmax = 375 nm (I), 460 nm (II) and 770 nm (III). The electrochemical transitions of PDMA while cycling the potentials were simultaneously monitored through UV-VIS spectroscopy. Results of cyclic spectrovoltammetry experiments revealed that the band at λmaxII = 460 nm corresponds to intermediate state between leucoemeraldine and emeraldine forms of PDMA. Hysteresis were noticed in the absorbance-potential profile for λmax = 375, 460 and 770 nm. The derivative cyclicvoltabstogram (DCVA) deduced from spectrovoltammetry reveals the presence of residual absorbance at E = 0.0 V for PDMA. A linear correlation was noticed between half intensity of absorbance (E1/2A) at the wavelength 375, 460 and 770 nm and scan rate (ν). Electrochromic properties of PDMA like optical contrast, columbic efficiency and electrochromic efficiency are reported.

Original languageEnglish
Pages (from-to)155-163
Number of pages9
JournalSynthetic Metals
Volume130
Issue number2
DOIs
Publication statusPublished - 2002 Sept 20

All Science Journal Classification (ASJC) codes

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

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