Polypyrrole characterization

Besides synthesis, current basic research on conducting polymers is concentrated on structural analysis. Structural parameters — e.g. regularity and homogeneity of chain structures, but also chain length — play an important role in our understanding of the properties of such materials. Research on electropolymerized polymers has concentrated on polypyrrole and polythiophene in particular and, more recently, on polyaniline as well, while of the chemically produced materials polyacetylene stih attracts greatest interest. Spectroscopic methods have proved particularly suitable for characterizing structural properties These comprise surface techniques such as XPS, AES or ATR, on the one hand, and the usual methods of structural analysis, such as NMR, ESR and X-ray diffraction techniques, on the other hand. 

X. Zhang, J. Zhang, R. Wang, T. Zhu, and Z. Liu, Surfactant-directed polypyrrole/CNT nanocables synthesis, characterization, and enhanced electrical properties. ChemPhysChem 5, 998—1002 (2004). 

Electrochemical communication between electrode-bound enzyme and an electrode was confirmed by such electrochemical characterizations as differential pulse voltammetxy. As shown in Fig. 11, reversible electron transfer of molecularly interfaced FDH was confirmed by differential pulse voltammetry. The electrochemical characteristics of the polypyrrole interfaced FDH electrode were compared with those of the FDH electrode. The important difference between the electrochemical activities of these two electrodes is as follows by the employment of a conductive PP interface, the redox potential of FDH shifted slightly as compared to the redox potential of PQQ, which prosthetic group of FDH and the electrode shuttling between the prosthetic group of FDH and the electrode through the PP interface. In addition, the anodic and cathodic peak shapes and peak currents of PP/FDH/Pt electrode were identical, which suggests reversibility of the electron transport process. 

Joshi PP, Merchant SA, Wang YD, Schmidtke DW (2005). MEMS sensor material based on polypyrrole-carbon nanotube nanocomposite film deposition and characterization. J. Micromech. Microengin. 5 2019-2027. 

Extremely thin, self-supporting film electrodes have been successfully produced. For example, polypyrrole films of 120 nm thickness have been used successfully to grow microcrystallites, followed by removal of the film plus crystallites from the substrate for characterization of the crystallographic structure and orientation of the microcrystallites by transmission electron microscopy with selected area electron diffraction [23]. Thin-film electrodes have been applied to allow transmission of high-energy beams, including x-rays, for in situ... 

The intractability of the conducting polymers makes characterization difficult and this in turn slows the development of better polymers. The precursor routes are very attractive because they provide intermediate polymers which can be properly characterized. A precursor for polypyrrole or polythiophene would greatly enhance our ability to understand the structure of the polymers produced electrochemically. 

It has been shown that the thickness of the polypyrrole (PPy) film has a significant effect on the electrode performance.17 Figure 6 shows the dependence of the response of PPy/PQQ modified electrode to 10 mM DMAET (A) and 10 mM DEAET (B) as a function of PPy film thickness. As film thickness increases the oxidation current increases for both DMAET and DEAET, presumably due to increases in the amount of PQQ loaded in the PPy film. The maximum current for the oxidation of PQQH2 is observed when 200 nm films are used. When the PPy film thickness was larger then 200 nm a decrease in the sensor response was observed, which could be due to increased resistance (R ) of the thicker film. The optimum 200 nm PPy film thickness was used to characterize the performance of the electrode for amperometric detection of thiols. 

More recent studies have focussed on the characterization of the conductive polymer, polypyrrole, and its use as a coating for acoustic wave vapor sensors [74-77]. One advantage of polypyrrole is that it can be generated directly on an... 

Nazzal AI, Street GB, Wynne KJ (1985) Characterization of polypyrrole. In Labes MM (ed) Molecular crystals and liquid crystals. Gordon and Breach Science Publishers, New York London Paris Montreux Tokyo, p 303 Neckel A (1987) Microchlm Acta [Wien] 3 263-280 Neddersen J, Chumanov G, Cotton TM (1993) Appl Spectrosc 47 1959 Neddersen IP, Mounter SA, Bostick JM, Johnson OK (1989) J Chem Phys 90 4719 Nees F (1978) Thesis, Karlsruhe Nees FW, Buback M (1976) Z Naturfor.sch 3la 1960 Neppel A, Butler IS, Eisenberg A (1979) Macromolecules 12 948 Nestor JR, Lippincott ER (1973) J Raman Spectrosc 1 305... 

Different electron-conducting polymers (polyaniline, polypyrrole, polythiophene) are considered as convenient substrates for the electrodeposition of highly dispersed metal electrocatalysts. The preparation and the characterization of electronconducting polymers modified by noble metal nanoparticles are first discussed. Then, their catalytic activities are presented for many important electrochemical reactions related to fuel cells oxygen reduction, hydrogen oxidation, oxidation of Cl molecules (formic acid, formaldehyde, methanol, carbon monoxide), and electrooxidation of alcohols and polyols. 

R. A. Simon, A. J. Ricco, and M. S. Wrighton, Synthesis and characterization of a new surface deriva-tizing reagent to promote the adhesion of polypyrrole films to n-type silicon photoanodes N-(3-(trimethoxysilyl)propyl)pyrrole, J. Am. Chem. Soc. 104, 2031, 1982. 

Ghosh et al. characterized polyaniline/IL composites with the help of NMR [72] and found no reactivity between the two components. Similar findings have been reported by Pringle et al. [73], who synthesized polypyrrole in an phosphonium-based IL. 31P, 19F, and 13C solid state NMR revealed incorporation of the IL during film growth which could easily be eliminated from the polymer via oxidation. 

Procedure proposed by Papirer et al. [28,37-39,53] was used in characterization of silicas, modified silicas, oxides and minerals. Authors of refs. [23-28,30,54] used this method for characterization of carbon fibers, solid polymers, i.e. conducting polypyrroles, polycarbonates and poly (dimethacrylates), respectively. Voelkel and Krysztafkiewicz [55] characterized silicas modified by organic compounds. 

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