Electrical conductivity polypyrroles

Fig. 122. Polymerization of pyrrole monomer in a preformed ferric stearate multilayer film (black dots represent electrically conducting polypyrrole) [764]...

Because of its high stability and its good electrical conductivity polypyrrole (PPy) can be used in many technical applications, e.g., in the field of microchips and microstructured electronic devices. Polypyrrole can also be used as a material in sensor technology. The interaction of different gases wifii the polymer structure can be detected by the paramagnetic resonance [1] or electrical conductivity measurements... 

In addition to showing high electrical conductivity, polypyrrole films can be repeatedly electro-chemically driven or switched between the blue-black conducting (100ohm cm ) oxidized form and a yellow nonconducting neutral. The switching rate for thin films is approximately 1 per second. 

Dong and Jones Jr. reported on the preparation of submicron electrically conductive polypyrrole/poly(methyl methacrylate) coaxial fibers and conversion to polypyrrole tubes and carbon tubes [47]. In this study, PMMA fibers with an average diameter of 230 nm were initially fabricated by electrospinning as core materials. The PMMA fibers were subsequently coated as templates with a thin layer of PPy by in situ deposition of the conducting polymer from aqueous solution. Hollow PPy nanotubes were produced by dissolution of the PMMA core from PPy/PMMA coaxial fibers. Furthermore, high temperature (1000 °C) treatment under an inert atmosphere can be used to convert PPy/PMMA coaxial fibers into carbon tubes by complete decomposition of the PMMA fiber core and carbonization of the PPy wall (Figure 4.13). 

S. Nair, S. Natarajan, and S. H. Kim, Fabrication of electrically conducting polypyrrole-poly(ethylene oxide) composite nanofibers, Macromolec. Rapid Commun., 26, 1599-1603... 

Polypyrrole Apolymer of pyrrole, afive-membered heterocyclic substance with one nitrogen and four carbon atoms and with two double bonds. The polymer can be prepared via electrochemical polymerization. Polymers thus prepared are doped by electrolyte anion and are electrically conductive. Polypyrrole is used in lightweight secondary batteries, as electromagnetic interference shielding, anodic coatings, photoconductors, solar cells, and transistors. 

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). 

No.8, 1993, p. 1649-52 FOURIER TRANSFORM-RAMAN SPECTROSCOPIC STUDY OF ELECTRICALLY CONDUCTING POLYPYRROLE FILMS... 

Kang, T.S., et al. 2005. Electrically conducting polypyrrole fibers spun by electrospinning. Synth Met 151 61. 

Gorman, C.B., H.A. Biebuyck, and G.M. Whitesides. 1995. Fabrication of patterned, electrically conducting polypyrrole using a self-assembled monolayer A route to all-organic circuits. Chem Mater 7 526. 

Choi, M.S., et al. 2002. Photolithographic patterning of electrically conducting polypyrrole film. 

Cen, L., K.G. Neoh, and E.T. Kang. 2002. Surface functionalization of electrically conductive polypyrrole film with hyaluronic acid. Langmuir 18 8633. 

Tessier, D., L.H. Dao, Z. Zhang, M.W. King, and R. Guidoin. 2000. Polymerization and surface analysis of electrically conductive polypyrrole on surface-activated polyester fabrics for biomedical applications. J Biomat Sci—Polym Ed 11 87. 

J. M. Kern, J. P. Sauvage, Photochemical deposition of electrically conducting polypyrrole, Chemical Communications 1989, 10, 657. 

R. E. Myers, Chemical oxidative polymerization as a synthetic route to electrically conducting polypyrroles, Journal of Electronic Materials 1986, 15,61. 

Li, Y Neoh, K. G. Cen, L. Kang, E. T. Porous and electrically conductive polypyrrole—poly(vinyl alcohol) composite and its applications as a biomaterial. Langmuir 1005, 23, 10702-10709. 

Aniline is used as a chemical intermediate to prepare isocyanates for making polyurethanes, antioxidants, and vulcanization accelerators, as well as in the manufacture of agricultural fungicides, herbicides and insecticides and in the preparation of certain dyes. Similarly, pyrrole is used as a chemical intermediate in the preparation of electrically conducting polypyrrole by means of an electrochemical polymerization process. Pyrrole has few other industrial uses. 

M. Nakata, Y. Shiraishi, M. Taga, and H. Kise, Synthesis of electrically conductive polypyrrole films by interphase oxidative polymerization, Makromol. Chem. 193 165 (1992). 

S. P. Armes and B. Vincent, Dispersions of Electrically Conducting Polypyrrole... 

The use of the electric field has been proposed and demonstrated to perform very well in defining various other properties. For example, electrical measurements have been used to monitor the foaming process and polymerization of polymeric foams [74], while dielectric measurements have been used for measuring the density of polymer foams [75]. Brady et al. [76] developed electrically conductive polypyrrole-coated PUR foam. The conductance of the foam was found to change linearly with the compressive load applied single and repeated. For aluminum foams, Kim et al. [77] developed a set of mathematical relationships based on experimental data to obtain mechanical properties (elastic modulus, compressive strength, and densification strain), using electrical conductivity as a non-destructive inspection method. 

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