Polypyrrole coatings

Fig. 6. Thermal stability of epoxy-encapsulated poly(pyrrole tosylate) film,, 0.5 Q/sq, and polypyrrole-coated textiles, D, 20 Q/sq, with exposure to...

FIG. 8 Si02 AFM image of six bilayers in situ self-assembled layer-by-layer films of polypyrrole coated with Si02 and poly(styrene sulfonate). 

LiMii204) electrochemical kinetics ensure that all of the surfaces of the nanotubules remain accessible to solvent and electrolyte. The polypyrrole coat was deposited by simply applying 5 al of a solution that was 1 M in HCIO4 and 0.2 M in pyrrole to the LiMn204 surface. This results in oxidative polymerization of all of the pyrrole, yielding 0.065 mg of polypyrrole per cm of Pt substrate surface [125]. 

In order to determine whether the new nanotubule electrode shows improved performance, a control electrode composed of the same material but prepared via a more conventional method is required. This control LiMn204 electrode was prepared by applying the precursor solutions described above directly onto a 1 cm Pt plate and thermally processing as before. Scanning electron micrographs showed that these films consisted of LiMn204 particles with diameters of —500 nm [124]. Spectrophotomet-ric assay showed that this control electrode also contained 0.75 mg of LiMn204 per cml A polypyrrole coat identical to that applied to the tubular electrode (0.065 mg) was also applied to this control electrode. 

Photoinduced Changes in Phase Boundary Potentials. The photoinduced membrane potentials were measured by using PVC matrix liquid membranes in contact with a polypyrrole-coated Pt electrode [dibutyl phthalate (DBP) as the membrane solvent]. The polypyrrole layer allows to obtain a stable and sample-in-dependent potential drop between Pt and the PVC membrane. The phase boundary potential at the interface of a membrane containing ionophore and an aqueous RbCl or KCl solution could be reversibly altered by UV and visible light irradiation, as shown for ionophore 89 in Figure 23a,b. The values of the photoinduced potential... 

In all the cases of poly acetylene, polythiophene, and polypyrrole coating, the amount of plasma-film deposition was different, caused by the difference in the structure of the three different monomers and their reactivity during the plasma process. PPy- and PTh-silica are more hydrophobic than PA-silica, probably due to the presence of different chemical moieties in the complex film structure deposited onto the silica surface. 

Blocking treatment with fresh solution (20 pi) of 5% (w/v) bovine serum albumin (BSA) in PBST (0.1 M phosphate buffer sahne (PBS) containing 0.5% (w/v) Tween 20, pH — 7) for 1 h at room temperature to prevent non-specific binding of avidin onto the polypyrrole coating. 

H. Shinohara, G. F. Khan, and M. Aizawa, Electrochemical oxidation and reduction of PQQ using a conducting polypyrrole-coated electrode, J. Electroanal. Chem. 304, 74-84 (1991). 

J. C. Wu, Z. Mester, J. Pawliszyn, Speciation of organoarsenic compounds by polypyrrole-coated capillary in tube solid phase microextraction coupled with liquid chromatography/electrospray ionisation mass spectrometry, Anal. Chim. Acta, 424 (2000), 211-222. 

Wang, Y. and Northwood, D.O., An investigation into polypyrrole-coated 316L stainless steel as a bipolar plate material for PEM fuel cells, J. Power Sources, 163(1), 500, 2006. 

As a result of the advances in catalyst discovery for aqueous ethylene polymerization, silica-polyethylene nancomposites have been prepared with structures that vary with changing catalyst structure and silica composition." It is likely that many more advances in the area of high-tech composites with potential biological and nanotechnology applications will be made in the next few years through aqueous polymerization processes. In addition to free radical polymerizations and catalytic polymerizations, it should be noted that oxidative polymerizations can also be performed in aqueous media to yield conducting polymers. Recently, this has been used to prepare polypyrrole-coated latex particles that are expected to be interesting synthetic mimics for micrometeorites. 

CLEC Polypyrrole-coated PS L-proline Cu(II) Amino acids [9]... 

Table 1 summarizes the LEC studies since 1990. As a stationary phases for CLEC, the weakness of resin microspheres is in their low column efficiencies. The study of polypyrrole-coated polystyrene microspheres presented an effort to overcome the weakness, where a second electrokinetic interaction was added in addition to the coordination interaction. A high protein adsorption is always needed as a stationary phase for IMAC. The study of PHEMA microspheres modified with dye plus metal ion was interesting, where the protein adsorption was greatly increased by metal complexion plus dye affinity. 

Lee, H.S. Hong, J. Chiral and electrokinetic separation of amino acids using polypyrrole-coated adsorbents. J. Chromatogr., A 2000, 868, 189-196. 

H. Yoneyama, K. Wakamoto, and H. Tamura, Photoelectrochemical properties of polypyrrole-coated silicon electrodes, J. Electrochem. Soc. 132 2414, 1985. 

R. E. Malpas and B. Rushby, The stability of two-layer ferrocene/polypyrrole-coated n-Si electrodes in aqueous photoelectrochemical photovoltaic cells, J. Electroanal. Chem. 157, 387, 1983. 

Ohtsuka, T, lida, M., and Ueda, M. 2006. Polypyrrole coating doped by molybdo-phosphate anions for corrosion prevention of carbon steels. Journal of Solid State Electrochemistry 10, 714-720. 

Fig. 25 Sensor response for polypyrrole coated fiber upon DMMP exposure...

FIGURE 1.8 Example of electrochromic device based on polypyrrole-coated glass. 

Chromatographic Interactions on Polypyrrole-Coated C18 (a Silica-Based Phase Coated with an Octadecyl Carbon Chain)... 

A method for analysis of polar pesticides in wine by the use of automated in-tube SPME coupled with LC/ESI-MS was proposed (Wu et al., 2002). In-tube SPME is a microextraction and preconcentration technique that can be coupled on-line with high-performance liquid chromatography (HPLC), suitable for the analysis of less volatile and/ or thermally labile compounds. This technique uses a coated open tubular capillary as an SPME device and automated extraction. Using a polypyrrole coating, six phenylurea pesticides (diuron, fluometuron, linuron, monuron, neburon, siduron) and six carbamates (barban, car-baryl, chlorpropham, methiocarb, promecarb, propham) were analyzed in wine. Structures of compounds are reported in Fig. 9.4. Due to the high extraction efficiency of the fiber toward polar compounds, benzene compounds, and anionic species, LODs ranging between 0.01 and 1.2pg/L were achieved, even if the sample ethanol content affects the recoveries of analytes. 

An automated in-tube solid-phase microextraction HPLC method for NNK and several metabolites have been developed by Mullett et al. ° In-tube SPME is an on-line extraction technique where analytes are extracted and concentrated from the sample directly into a coated capillary by repeated draw-eject steps. A tailor-made polypyrrole-coated capillary was used to evaluate their extraction efficiencies for NNK and several metabolites in cell cultures. This automated extraction and analysis method simplified the determination of the tobacco-specific A-nitrosamines, requiring a total sample analysis time of only 30 min. 

The influence of surface coating on the microwave reflectivity of a polypyrrole coated honeycomb is... 

The stabilities of polypyrrole-coated conductive fabrics were highly dependent on the doping counterion as well as the polymerization conditions. The rate of degradation showed a diffusion controlled kinetics at high temperatures. The room temperature half-life for the most stable conductive fabric was estimated to be about five years [129]. 

N.V. Krstaijic, B.N. Grgur, S.M. Jovanovic and M.V. Vojnovic. Corrosion protection of mild steel by polypyrrole coatings in acids sulfate solutions. Electrochem. Acta, 1997, Vol. 42, No. 11, pp. 1685-1691. 

R. A. Bull, F.-R. F. Fan and A. J. Bard, Polymer films on electrodes VII. Electrochemical behavior at polypyrrole-coated platinum and tantalum electrodes, J. Electrochem. Soc. 129 (1982) 1009-1015. 

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