Polypyrrole doping

Figure 3.70 Room temperature optical absorption spectra of a 45(X)A-lhick film of neutral polypyrrole doped with at0.03 torr. (a) before exposure to I2, conductivity <10 6fl 1cm"1 (b) after 2 minutes I2 exposure, conductivity 4.8 ft em 1 (c) after 7 minutes exposure, conductivity 6,7 ft em 1 (d) after 22 minutes I2 exposure, conductivity 32ft cm The three structures seen on the low-energy side of (a) (c) arc possibly artifacts due to interference effects in the films. From Pfluger et at. (1983).

Fig. 11. Stress-strain behavior of a) polypyrrole doped with p-toluene sul-phonate and b) the same polymer plasticised with acetonitrile. Reproduced with permission from Wynne KJ, Street GB (1985) Macromolecules 18 2361...

The use of ISEs with ion-selective membranes based on plasticized PVC, as well as glass pH electrodes, is limited to the analysis of aqueous solutions. On the other hand, sensors based on conducting polymer membranes are usually insoluble in organic solvents, which extends the range of possible applications. Electrosynthesized polypyrrole doped with calcion works as a Ca2+ sensor that can be applied as indicator electrode in the titration of Ca2+ with NaF in mixed solvents, such as water-methanol (1 1) and water-ethanol (1 1) [52], Another example is the use of polyaniline as indicator electrode in order to follow the acid-base precipitation titration of trimeprazine base with tartaric acid in isopropanol solution (see Procedure 5). 

Metallic polymers have a lower density of electrons both the length of the repeat unit along the chain and the interchain spacing are relatively large compared to the interatomic distances in conventional metals. Typically, for metallic polymers N is of the order 5 x 10 cm . Thus, for metallic polymers, the plasma frequency is at approximately 1 eV [66,67]. The reflectance of high quality, metallic polypyrrole (doped with PF ) is shown in Fig. III-2. Metallic polymers exhibit high reflectance (and thus look shiny ) in the infrared, but they are semitransparent in the visible part of the spectrum. The residual absorption... 

Fig. 1.16 Broad Q neutron scattering for a sample of per-deuterated polypyrrole doped with deuterated toluene sulfonate. The full line shows the data for Q perpendicular to the film surface and the points show the data for Q parallel to the film surface.

The immobilisation of antibacterial coatings onto conductive materials such as stainless steel or carbon fibre used in orthopaedic implants was investigated by two methods. The formation of thin films by electrodeposition of polypyrrole doped with polyanions able to complex silver ions, and their characterisation by SEM, FTIR and microbiological testing is described. The alternative method, involving chemical grafting of a thin film of a quatemaiy ammonium polymer using a surface initiator, is also discussed. 2 refs. 

Polypyrrole doped with organic surfactant anions... 

Polypyrrole doped with transition-metal complex anions... 

Chemical oxidation of neutral polyacetylene or polypyrrole with SnCl4 results in the insertion of SnCl5" anions as the dopants. In the case of polypyrrole, SnCl5 can be alternatively introduced to the polymer as a result of an acid-base reaction between polypyrrole doped with Cl" anions and SnCU [84,105] ... 

The preparation of polypyrrole doped with sulpho-nated metallocyanine anions and other complex anions gave rise to detailed Mossbauer effect studies in these systems. It should be stressed that Mossbauer spectroscopy of the above mentioned compounds is more complex than in the case of polypyrrole doped with metal halides or metal cyanides. 

C.O. Yoon, M. Reghu, D. Moses, and A.J. Heeger, Transport near the Metal-Insulator-Transition - Polypyrrole Doped with Pf(6), Phys. Rev. B, 49, 10851-10863 (1994). 

T. Zama, S. Hara, W. Takashima, and K. Kaneto, Comparison of conducting polymer actuators based on polypyrrole doped with BF4-, PFe, CF3SO3, and CIO4, Bull. Chem. Soc. Jpn.,78 (3), 506-511 (2005). 

G. Paliwoda-Porebska, M. Rohwerder, M. Stratmann, U. Rammelt, L.M. Due, and W. Plieth, Release mechanism of electrodeposited polypyrrole doped with corrosion inhibitor anions, J. Solid State Electrochem., 10, 730-736 (2006). 

H.K. Song, B. Toste, K. Ahmann, D. Hoffman-Kim, and G.T.R. Palmore, Micropattems of positive guidance cues anchored to polypyrrole doped with polyglutamic acid A new platform for characterizing neurite extension in complex environments. Biomaterials, 27, 473-484 (2006). 

Shahrokhian, S., and Asadian, E. (2009). Electrochemical determination of L-dopa in the presence of ascorbic acid on the surface of the glassy carbon electrode modified by a bllayer of multi-walled carbon nanotube and polypyrrole doped with tlron, J. Electroanal. Chem., 636, pp. 40-46. 

Yoon, C.O., et al. 1994. Transport near the metal-insulator transition Polypyrrole doped with PFe. Phys Rev 5 49 10851. 

Syritski, V., A. Opik, and O. Forsen. 2003. Ion transport investigations of polypyrroles doped with different anions by EQGM and GER techniques. Electrochim Acta 48 1409. 

Stauffer, W., and X.T. Cui. 2006. Polypyrrole doped aith 2 peptide sequences from laminin. Biomaterials 27 2405. 

Bay, L., S. Skaarup, K. West, T. Mazur, O. Joergensen, and H.D. Rasmussen. 2001. Properties of polypyrrole doped with alkylbenzene sulfonates. Presented at the Proceedings of the SPIEs 8th International Symposium on Smart Structural Materials, Electroactive Polymer Actuators and Devices (EAPAD), Newport Beach, CA. 

A conductive polymer film of polypyrrole doped with polymolybdate anions was electrodeposited onto steel and found to provide corrosion protection in neutral and acidic 3.5% NaCl solution [152]. The anodic codeposition of polypyrrole and Ti02 onto mild steel in an oxalic acid medium has been described [153,154]. The PPy and Ti02 composite showed a considerable improvement in anticorrosion properties with respect to PPy films in salt spray and weight-loss tests. It was suggested that these composite films could be applied as a primary coating replacement for the phosphatized layers on mild steel [154]. 

Joo, J., and M. Pyo. 2003. Effects of cationic species on strain changes of polypyrrole doped with perchlorate anions. Electrochem Solid-StateLett 6 E27. 

Song, E.-H. and W.-K. Paik (1998). Polypyrrole doped with sulfonate derivatives of metalloporphyrins Use in cathodic reduction of oxygen in acidic and basic solutions. Bull. Korean Chem. Soc. 19(2), 183-188. 

Metalate anion is also incorporated in the conducting polymer as a dopant. Tungsten oxide is a typical electrochromic inorganic molecule. An electrochromic conducting polypyrrole doped with phosphotungstate ions was investigated. It showed four colour chromisms which were attributed to chromisms of both phosphotungstate and polypyrrole [12]. 

---