Title of article :
In situ UV–visible spectroelectrochemical studies on electrochromic behavior of poly(2,5-dimethoxy aniline)
Author/Authors :
Huang، نويسنده , , Li-Ming and Wen، نويسنده , , Ten-Chin and Gopalan، نويسنده , , A، نويسنده ,
Issue Information :
دوماهنامه با شماره پیاپی سال 2002
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 (0.70 V for PANI and 0.27 V 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.
Keywords :
Poly(2 , UV–vis spectroscopy , hysteresis , Derivative cyclicvoltabstogram (DCVA) , 5-dimethoxyaniline) , Electrochromic properties
Journal title :
Synthetic Metals
Journal title :
Synthetic Metals