Polypyrrole chemical structure

Fig. 7 Examples of the chemical structure of intrinsically conducting polymers. The structure shown is nonconducting. The metal like conductivity is obtained by chemical or electrochemical oxidation. This is shown for polypyrrole as an example in Fig. 8...

R. McNeill, R. Siudak, J. Wardlaw, D. Weiss, Electronic Conduction in Polymers. I. The Chemical Structure of Polypyrrole. Aust. J. Chem. 1963,16, 1056. 

Figure 15.7 Chemical structure of (a) polyaniline (leu-coemeraldine), (b) polypyrrole, and (c) poly(ethylene dioxythiophene).

The chemical structure of electrically conducting polypyrrole films doped with p-toluene sulfonate and dodecyl sulfate was studied by FT-Raman spectroscopy. The spectra were compared with those from the corresponding reduced polymers after dedoping and found to be consistent with polaron and bipolaron descriptions of the electron transport mechanism in polypyrrole (331). 

FIGURE 8.13 Chemical structures of the various comonomers used to synthesize the reactive statistical copolymers required for the preparation of sterically stabilized polypyrrole particles. (From Simmons, M.R., Chaloner, RA., and Armes, S.P., Langmuir, 14, 611, 1998. With permission.)... 

FIGURE 16.4 (a) Schematic representation of the chemical structure of neutral ideal lineal chain of polypyrrole,... 

Figure 8.1 Chemical structures of (a) polyacetylene, (b) polythiophene, (c) polypyrrole, and (d) polyanUine.

Polyaniline, PAni Polypyrrole, PPy Polythiophene, Pth Scheme 2. Chemical structures of three important CPs (neutral state). 

Figure 1.10 Evolution of the polypyrrole band structure upon doping (a) low doping level, polaron formation (b) moderate doping level, bipolaron formation (c) high doping level (33 mol%), formation of bipolaron bands. (Reprinted with permission from Accounts of Chemical Research, 18, 309. Copyright (1985) American Chemical Society.)...

Cyclic voltammetry can be used to estimate the charge transfer rate and also evaluate how this rate depends on parameters such as morphology and the chemical structure. The cyclic voltammetric examination of electroactive polymers is usually done in monomer-free solutions containing only the solvent and supporting electrolyte. In order to avoid the complication of mixed electrolytic equilibria, the supporting electrolyte and the solvent are usually the same as employed for the polymerization. Figure 3 shows the cyclic voltammogram (CV) of a polypyrrole film prepared in acetonitrile/tetra-w-butyl ammonium fluoborate medium. The anodic peak corresponds to polypyrrole oxidation, while the cathodic one corresponds to the reduction of this species. 

The chemical structure of the counterion may have a profound influence on the morphology and conductivity of the polymer. For instance, polypyrrole made in the presence of dodecyl sulfate is very smooth, dense, stable, and highly conducting, whereas polypyrrole made in the presence of perchlorate ion has a cauliflower morphology and its conductivity is about 100 times lower than with dodecyl sulfate. Apparently long-chain anions have a kind of aligning effect on the polymer chains. Also, anions and other... 

Truong V-T (1992) Thermal degradation of polypyrrole effect of temperature and film thickness. Synth Met 52 33-44 Van Beusichem B, Ruberto MA (2005) Introduction to polymer additives and stabilization. A presentation to product quality research institute http //www.pqri.org/... /posters/Polymer Additives PQRI Poster.pdf Accessed 26 June 2011 Van Krevelen DW, Nijenhuis KT (2009) Properties of polymers. Their correlation with chemical structure their numerical estimation and prediction from additive group contributions, 4th edn. Elsevier, Amsterdam Wang Y, Rubner MF (1990) Stability studies of the electrical conductivity of various poly (3-alkylthiophenes). Synth Met 39 153-175... 

Figure 4-1. Chemical structures of conducting polymers, (a) Frans-polyacetylene (b) cw-polyacetylene (c) poIy(/i-phenylene) (d) polypyrrole (e) polythiophene (f) poly(/>-phenylenevinylene) (g) poly(2,5-thienylenevinylene) (h) polyaniline (leucoemeraldine base form) (i) polyisothianaphthene.

Conducting polymers are chemically characterized by the so-called conjugation, in which carbon double bonds alternate with carbon single bonds along a polymer backbone. The chemical structures of two examples of conducting polymers, polypyrrole (PPy) and polyaniline (PANi), are reported in Fig. 6.101. 

Figure 20.23 (A) Schematic of a typical oCVD reactor. (B) Chemical structures of conductive polymer deposited by oCVD. PEDOT PPy, polypyrrole PTAA, poly(3-thiopheneacetic acid) [147], (With permission from Elsevier).

Fig. 3.1 Schematic chemical structures of polyacetylene, polyaniline, and polypyrrole.

In the following, three examples of conductive polymers will be discussed because these are the most commonly used in biosensors. Table 17.1 shows the chemical structures of polypyrrole, polyaniUne and PEDOT, the three conductive polymers reviewed in this section. 

Table 17.1 Chemical structure of polypyrrole, PEDOT, polyaniline...

The specific type of surface active pyrrole derivative used to form the monolayer was found to strongly influence the chemistry that is initiated at the air-water interface. For example, when solutions containing a 5000/1 mole ratio of pyrrole/3-octadecylpyrrole were spread onto the oxidizing subphase, copolymerization of the two monomers occurred as well as homopolymerization of the unsubstituted pyrrole monomer. The net result was a relatively thick surface film (100-200A) that was very difficult to transfer into multilayers via a conventional vertical lifting technique. With 3-octadecanoylpyrrole as the surface active component, on the other hand, copolymeiization of the two monomers was suppressed and only electrically conducting polypyrrole chains were formed. In this latter case, uniform monolayer films about 40 A thick were formed and these could be readily transferred into multilayer structures. The chemical structures of the molecules used in this particular system are presented in Scheme 3. 

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