Auger and infrared study of polypyrrole films: Evidence of chemical changes during electrochemical deposition and aging in air

Hahn, Stephen J.; Gajda, Walter J.; Vogelhut, P. O.; Zeller, M. V.

doi:10.1016/0379-6779(86)90130-x

Cited by 38 publications

(4 citation statements)

References 12 publications

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“…Step-2 corresponds to the oxidative degradation reactions of polymer backbone producing segments of various conjugation lengths (Mohammad et al 1993) involve substitution, addition and chain scission. The presence of resonances due to broad H-bonded -OH and C=O groups in the FTIR spectra of degraded polythiophene (BF4) (Mohammad 1988) are further supported by the work of Hahn et al (1986) Oxidative degradation of most polymers proceeds via chemical reactions of peroxy radicals. Yang and Chien (1985) reported autooxidation of polyacetylene, a typical unsaturated polymer with a long conjugated system, and a value of 9 x 10 ~ mol(g)s-1 for the rate constant at 70°C and 760 torr O z.…”

Section: It(k)mentioning

confidence: 91%

Thermal stability of electrochemically prepared polythiophene and polypyrrole

1995

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The degradation behaviour of electrochemically prepared polythiophene and polypyrrole has been studied by thermal gravimetric analysis technique. Studies on both the polymers show that they are more stable than polyacetylene but still undergo degradation reactions which involve two steps, viz. loss of dopant and then degradation of polymer backbone. The general features of degradation mechanisms are discussed.

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Section: It(k)mentioning

confidence: 91%

Thermal stability of electrochemically prepared polythiophene and polypyrrole

1995

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“…In most studies, electrochemical (11)(12)(13)(14) and spectroscopic (7,(15)(16)(17)(18)(19)(20) properties, conductivity data (4,20,21), and chemical degradations (22) were reported.…”

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confidence: 99%

Morphology and Electrochemical Properties of Polypyrrole Films Prepared in Aqueous and Nonaqueous Solvents

Rhee

Park

et al. 1990

J. Electrochem. Soc.

187

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Electrochemical characteristics, conductivities, and morphology of the polypyrrole (PPy) films prepared in aqueous and nonaqueous (acetonitrile) solutions by electrochemical techniques have been studied and the results are reported. Electrochemical parameters studied included exchange rate constants and capacitances for the films. PPy films prepared in acetonitrile were found to be superior to those prepared in aqueous medium in their electron transfer characteristics and conductivities. Films prepared in water were found to be more porous than their counterparts in acetonitrile. These differences in properties of the films prepared in different media were explained in terms of their morphology. The polarity and nucleophilicity of the solvent used for the synthesis of PPy films appeared to be responsible for different morphology of the PPy films.

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“…The series of sharp peaks between 1600 and 600 cm -1 is similar to those observed in the spectra of unsubstituted PPyr. [22][23][24] The peaks at around 1500 cm -1 can be assigned to CdC stretching modes of the pyrrole and benzene rings and C-N stretching vibration modes. The relative strong absorption above 2500 cm -1 indicates the presence of pyrrole CH (3100 cm -1 ), aliphatic CH (∼2900 cm -1 ), and probably hydrogenbridged pyrroles, carboxy groups, and water.…”

Section: Resultsmentioning

confidence: 99%

Composite Films of Prussian Blue and N-Substituted Polypyrroles: Fabrication and Application to Optical Determination of pH

1998

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A new and simple chemical method for deposition of thin blue films composed of Prussian Blue and N-substituted polypyrroles on nonconductive supports is presented. It is found that only pyrroles which are difficult to polymerize can be used for the preparation of such films. The resulting composite films were examined by SEM-EDAX, vis-NIR, and IR spectroscopy. The films are stable, thin, homogeneous, and optically transparent. The absorption maxima are at 720 nm, and spectral changes can be monitored using semiconductor light sources and detectors. The composite films are shown to be suitable for optical determination of pH over the pH 5-9 range because their absorbance strongly depends on pH in the physiological pH range. However, they undergo irreversible spectral changes if exposed to pH's >9. The films represent an alternative to indicator-based pH sensor materials because they do not require a dye to be immobilized. The pH measurements are highly reproducible, reversible in the physiological range, and not affected by ionic strength, alkaline cations, and typical oxidants and reductants.

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Auger and infrared study of polypyrrole films: Evidence of chemical changes during electrochemical deposition and aging in air

Cited by 38 publications

References 12 publications

Thermal stability of electrochemically prepared polythiophene and polypyrrole

Thermal stability of electrochemically prepared polythiophene and polypyrrole

Morphology and Electrochemical Properties of Polypyrrole Films Prepared in Aqueous and Nonaqueous Solvents

Composite Films of Prussian Blue and N-Substituted Polypyrroles: Fabrication and Application to Optical Determination of pH

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