Coating with polyaniline

On both Pt and polyaniline-coated electrodes, diffusion-limited currents are observed at <250 mV for Fe(CN)500 mV for Fe(CN)g- oxidation. Potentiostatic EHD impedance was measured on both diffusion plateaux (50 mV and 550 mV), using Pt electrodes coated with polyaniline films of various thickness 50 and 130nm. As an example, the results obtained on the cathodic plateau are shown in Fig. 6-13 those observed on the anodic plateau were very similar [93]. 

Pringsheim, E. Zimin, D. Wolfbeis, O. S. Fluorescent beads coated with polyaniline. A novel nanomaterial for optical sensing of pH. Adv. Mater. 2001, 13, 819-822... 

Sathiyanarayanan, S., Azim, S.S., and Venkatachari, G., A new corrosion protection coating with polyaniline-TiO2 composite for steel, Electrochim. Acta, 52, 2068, 2007. 

Amongst others, the advantage of such an absorbant lies in the excellent structural properties conferred by the composite material (glass textile reinforcement coated with polyaniline-F epoxy matrix). Besides, this composite can be combined with other materials with which its mechanical and radioelectric properties are compatible (foams, honeycombs...), For example, a bandwidth at — lOdB between 5 and 20 GHz was obtained by adding only 4-5 kg/m to the starting composite material. 

Passivation of metals by coating with polyaniline corrosion potential shift and morphological changes... 

C. Su, G. Wang, and F. Huang, Preparation and characterization of composites of polyanihne nanorods and multiwalled carbon nanotubes coated with polyaniline, J. Appl. Polym. Sci., 106, 4241 247 (2007). 

B. Wessling, Passivation of metals by coating with polyaniline corrosion potential shift and morphological changes, Adv. Mat., 6, 226-228 (1994). 

Large quantities of textiles coated with polyaniline or preferably polypyrrole which apparently have significant use in various types of stealth operations have been and are being produced in relatively large quantities,. ... 

Liu, Y, Matsumura, T, Imanishl, N., Hirano, A., Ichikawa, T, and Thkeda, Y. (2005]. Preparation and characterization of Si/C composite coated with polyaniline as novel anodes for Li-ion batteries, Electrochem. Solid St, 8, pp. A599-A602. 

Y. Liu, T. Matsumura, N. Imanishi, A. Hirano, T. Ichikawa, Y. Takeda, Preparation and Characterization of SPC Composite Coated with Polyaniline as Novel Anodes for Li-Ion Batteries. Electrochem. Solid-State Lett. 2005, 8, A599. 

M. Paligova, J. Vilcakova, P. Sdha, V. Kfesdlek, J. Stejskal, O. Quadrat, Electromagnetic Shielding of Epoxy Resin Composites Containing Carbon Fibers Coated with Polyaniline Base. Phys Stat Mech Its Appl 2004, 335, 421-429. 

M. M. Castillo-Ortega, 1. Santos-Sauceda, J. C. Encinas, D. E. Rodriguez-Felix, T. del Castillo-Castro, E Rodriguez-Felix, J. L. Valenzuela-Garcia, L. S. Quiroz-Castillo, R J. Herrera-Franco, Adsorption and desorption of a gold-iodide complex onto cellulose acetate membrane coated with polyaniline or polypyrrole A comparative study. /Mater Sci 2011,46 (23), 7466-7474. 

Jin C, Nagaiah TC, Xia W, Spliethoff B, Wang S, Bron M, Schuhmann W, Muhler M (2010) Metal-free and electrocatalytically active nitrogen-doped carbon nanotubes synthesized by coating with polyaniline. Nanoscale 2(6) 981-987... 

Metal-free and electrocatalytically active nitrogen-doped carbon nanotubes synthesized by coating with polyaniline. Nanoscale, 2, 981—987. 

Figure 6. Optical spectra of transparent colored conductive coatings with polyaniline...

To investigate the corrosion process we took various specimens of steel coated with polyaniline and exposed them for a considerable period to two different corrosive environments a salt solution (a neutral 3.5% NaCl solu-... 

Table 19.6 shows some of the results obtained at the end of the measuring period by means of visual examination of the three types of specimens. It emerged from the studies that of the specimens exposed to the HCl environment, those coated with polyaniline were clearly the best protected against corrosion and rust. In the case of the NaCl environment the corrosion protection afforded by polyaniline appeared to be less effective than in the specimens exposed to the HCl environment. An untreated control specimen corroded within only a few hours. 

In general, mild steel samples coated with polyaniline in hydrochloric acid exhibited better corrosion protection than those exposed in sodium chloride solution under the same coating conditions as indicated simply by comparison of Eoc and corr as shown in Figs. 31.11-31.13. Corrosion samples tested in this study for all seven conductive polymers can be classified into one of the above three categories. 

Fig. 31.37 Bode plots of aluminum alloy 2024 uncoated, coated with polyaniline, and coated with polypyrrole and exposed to 3.57f NaCl.

Flg. 31.38 Potentiodynamic scans of aluminum alloy 7075 coated with polyaniline or polypyrrole and exposed to 3.5% NaCl. 

The plethora of data presented in this chapter and in the literature leaves no doubt that corrosion processes and mechanisms for inhibition are complex. Nonetheless, it is well established that conductive polymers can impart significant corrosion protection to selected metals such as steel, aluminum, and copper. Also, a picture is beginning to emerge of the corrosion inhibition mechanisms that rationalizes the observations made on corroding cold steel coated with polyaniline. For this system there are two cases to consider. Case I is where a steel surface exposed to a corrosive environment is completely covered by a coating of doped polyaniline. Case II is a case where a steel surface exposed to a corrosive environment is almost completely covered by a coating of doped polyaniline but also has small areas of bare steel exposed. 

M. Ikuo, Manufacture of electrically conductive polymer substrate coated with polyaniline, Jpn, Patent 03,119,612 (1991). 

Wessling B. (1994), Passivation of Metals by Coating with Polyaniline Corrosion Potential Shift and Morphological Chsages. AdvMater, 6,226-8. 

The polypyrrole particles attached to the fiber surface contributed to the rough morphology. Similarly, SEM micrographs have also revealed that surface of polypyrrole/ PE composite films were rougher compared to the smooth PE surface [25]. Moreover, a granular morphology for the surface of PE films coated with polyaniline has also been reported [40]. 

Surface coating with polyaniline Graphite felt 1.8-Fold increase in power density [96]... 

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