Electrochemical coatings

Lopez-Fonseca et al. [11] discussed the theory of reverse pulse polarography and the technique was applied in the determination of penicillamine electrochemically coated on a dropping-mercury electrode. Using long drop times and short pulses, the drug can be determined at levels as low as 50 nM in the presence of Cu(II), and the technique compares well with normal-pulse and differential-pulse polarography. 

Fig. 5.16 (a) (i) Schematic of the electrochemical coating of SWCNT connected cathode from a sacrificial silver cathode with SEM images (ii) before and (iii) after Ag NP decoration, (b) Examples of fractal patterns possible with continued deposition, arrows indicate original position of SWCNT. Scale bar in all SEM images represent 1 pm. Altered and reproduced with permission from [217],... 

Not much has been done in discussing ways to improve medical device surfaces using electrochemical coating methods in particular, with the aim of accomplishing the medically relevant goal, aside from discussion in the relevant literature, of the processing of nitinol (an alloy of nickel and titanium see Section 21.4). 

In conclusion, electrochemistry and electrochemical coatings play a crucial role in biomaterial-host interactions and constitute integral components in medical device design. Electrochemistry should be viewed as a tool that can work for or against the medical... 

Both SRET and SVET perform potentiometric measurements with micrometer-sized quasi-reference electrodes (typically platinum micro-cones electrochemically coated with platinum black) held precisely above the sample surface. So far these commercial instruments have not been designed to accommodate ion-selective microelectrodes. However, some groups have reported the use of home-made instruments to probe the concentration of specific ions (see Sec. V.B). 

This was the reason for the start of a deeper investigation with the goal of getting reproducible and significant improvements by using polyaniline coatings on metals without any electrochemical coating process. 

In order to form dopamine sensing devices, N-vinylcarbazole polymers were electrochemically coated onto xm sized carbon fibers [216]. As solutions, lithium perchlorate/acetonitrile, sodium perchlorate/acetonitrile, and tetraethylammonium tetratluoroborate/acetonitrile were used. In this way, dopamine sensing layers on the carbon fiber micro-electrodes were formed. 

Bidan, G., A. Deronzier, and J.-C. Moutet. 1984. Electrochemical coating of an electrode by a poly(pyrrole) film containing the viologen (4,4 -Bipyridinium) system. J Chem Soc Chem Commun 1185-1186. 

About 10 years ago, deBerry [68] found that a reduction in the corrosion rate could be delivered by electrochemical coating of prepassivated steel (in passivating enviromnent) with polyaniline (from aniline monomer). He supposed that the preformed passive state of the metal was maintained by the PAni layer. Troch-Nagels et al. [69], however, concluded that PAni, unlike polypyrrole, after electrochemical deposition under comparable conditions, did not offer any corrosion protection. 

Cosnier S, Deronzier A, Moutet J-C (1986) Electrochemical coating of a platinum electrode by a poly(pyrrole) film containing the Fac-Re(2,2 -bipyridine)(CO)3Cl system application to electrocatalytic reduction of CO2. J Electroanal Chem Interfacial Electrochem 207 (1-2) 315-321. doi 10.1016/0022-0728(86)87080-2... 

Havinga, E. E., Van Horssen, L. W., ten Hoeve, W., Wynberg, H., and Meijer, E. W., Self-doped water soluble conducting polymers, Polym. Bull., 18, 277-281 (1987). Bidan, G., Deronzier, A., and Moutet, J. C., Electrochemical coating of an electrode by a polypyrrole film containing the viologen (4,4 -bipyridinium) system, J. Chem. Soc. them. Commun., 1185-1186 (1984). 

In this section blends or composites obtained by the combination of two conductive polymers are discussed. Frequently, one conductive polymer is used as working electrode and is electrochemically coated with another conductive polymer. Some examples of conductive copolymers are also given here. Also, the anodic photocurrent generated by the irradiation of an n-type semiconductor can be used to coat with a conductive polymer layer or to form the tracks of a conductive polymer. Oxidation sites in intercalation compounds or in porous solids can be also used to obtain composites with conductive polymers. 

Evangelides, H A (1955), Method of Electrochemically coating magnesium and electrolyte there-for. US Patent 2723952. 

To evaluate the quality of the electrochemical coatings obtained from choline chloride based ionic liquids, constant current electrolyses were carried out under stationary conditions and in open air (the electrolyte has been in contact with atmospheric air and humidity). Different ionic liquids systems have been involved, as shown in Table 3. A two-electrode configuration has been employed, using various metallic substrates, respectively of Cu, A1 and Mg as metallic substrates, of 70x35 mm sizes, with a constant geometrical area of 24.5 cm2. Table 4 briefly presents the surface preparation of the metallic electrode before electrodeposition, as well as the electrolysis conditions. 

Florea, A. (2010), Metals and conducting polymers electrochemical coatings with controlled properties using ionic liquids media, Ph.D. Thesis, POLITEHNICA University, July 2010... 

---