Electropolymerization polyaniline

Y.-Q. Miao and J.-G. Guan, Probing of antibody-antigen reactions at electropolymerized polyaniline immunosensors using impedance spectroscopy. Anal. Lett. 37, 1053—1062 (2004). 

Fig. 9.9 CV and frequency-potential curves for the oxidation and re-reduction processes of the electropolymerized polyaniline film [26] (a) in 0.5 M LiCICVAN, and (b) in aqueous 0.5 M NaCl04+HCIO4 (pH = 1). Voltage sweep rate 5 mVs-1, quantity of film deposition 0.4Ccm-2, and SSCE = saturated NaCl calomel electrode.

Many of the earliest studies focused on the use of polymer-coated semiconductor materials for the reduction of C02. An example was the study of Aurian-Blajeni et al., who electropolymerized polyaniline onto p-Si [116]. In an aqueous C02-saturated solution, a total faradaic efficiency for formic acid and formaldehyde of 28% was achieved, but at a potential of—1.9 V (versus SCE). Likewise, Cabrera and Abruna electropolymerized [Re(CO)3(v-bpy)Cl], where v-bpy is 4-vinyl-4 -methyl-2,2 -bipyridine [117]. For CO production, TONs of about 450 were observed, while the faradaic efficiencies approached 100%. Upon illumination in acetonitrile solution, the onset potential for reduction was -0.65 V (versus SCE). 

Rossberg, K., G. Raasch, L. Dunsch, and S. Ludwig, The influence of porosity and the nature of the charge storage capacitance on the impedance behaviour of electropolymerized polyaniline films. Journal of Electroanalytical Chemistry, 1998. 443 p. 49... 

Many organic substances show electrochromism and can serve as ion storage layers in devices with W oxide films. Snch a device was reported by Yoshida et al. specifically it incorporated sputter-deposited W oxide, electropolymerized polyaniline, and an electrolyte of LiC104 + PC. Transmittance changes between 80 and 4% could be obtained with time constants of 10 s. The cycling dnrabihty was 5 x 10 times. 

Jha SK, Kanungo M, Nath A, D Souza SF (2009) Entrapment of live microbial cells in electropolymerized polyaniline and their use as urea biosensor. Biosens Bioelectron 24... 

Dutta K, Kundu PP (2013) Reversible assembly and disassembly of amphiphilic assemblies by electropolymerized polyaniline films effects rendered by varying the electropolymerization potential. J Phys Chem B 117 7797-7805... 

Besides synthesis, current basic research on conducting polymers is concentrated on structural analysis. Structural parameters — e.g. regularity and homogeneity of chain structures, but also chain length — play an important role in our understanding of the properties of such materials. Research on electropolymerized polymers has concentrated on polypyrrole and polythiophene in particular and, more recently, on polyaniline as well, while of the chemically produced materials polyacetylene stih attracts greatest interest. Spectroscopic methods have proved particularly suitable for characterizing structural properties These comprise surface techniques such as XPS, AES or ATR, on the one hand, and the usual methods of structural analysis, such as NMR, ESR and X-ray diffraction techniques, on the other hand. 

Although much less so than pyrrole polymers, indole polymers are beginning to be synthesized and studied as new materials. Electropolymerized films of indole-5-carboxylic acid are well-suited for the fabrication of micro pH sensors and they have been used to measure ascorbate and NADH levels. The three novel pyrroloindoles shown have been electrochemically polymerized, and the polymeric pyrrolocarbazole has similar physical properties to polyaniline. 

Wang, D.-W., et ah, Fabrication ofgraphene/polyaniline composite paper via in situ anodic electropolymerization for high-performance flexible electrode. ACS Nano, 2009. 3(7) p. 1745-1752. 

Biosensors based on carbon fiber ultramicroelectrodes have been used to determine pyruvate (2) and glucose (3). Glucose sensors using platinum ultramicroelectrodes have also been reported (4), including the entrapment of glucose oxidase in an electropolymerized film of polyaniline (5,6). Ikariyama and co-workers have used platinum ultramicroelectrodes modified with platinum black to construct very sensitive glucose sensors (7-13). 

Electropolymerization can also be used for the design of molecularly imprinted polymers (MIPs), capable of interacting with the analyte (template) molecule with high affinity and specificity (103,104). This is accomplished by electropolymerizing polypyrrole, polyaniline, or poly(o-phenylenediamine) in the presence of the analyte (template) molecule. At the end of the polymer-... 

The formation of conductive conjugated polymers [e.g., polyacetylene, polypyrrole, polythiophene, polyaniline and poly(p-phenylene)] [92, 94] on electrodes by electropolymerization has been studied thoroughly [95]. If the electropolymerization is performed in a solution containing both the monomer and enzyme, then enzymes present in the immediate vicinity of the electrode surface become trapped in the... 

Oxide, flouride, and polymeric films, as well as certain others, are used as protective coatings for HTSC materials (for example, see [505]). The electrodeposition of conducting polymers such as polypyrrole [433,491, 493, 506], polythiophene and its derivatives [493, 507], and polyaniline [478] is the most effective process. Anodic electropolymerization in acetonitrile solutions proceeds without any degradation of the HTSC substrate and ensures continuous and uniform coatings. Apparently, this method is promising not only for the fabrication of compositions with special properties based on HTSC [50, 28,295] as mentioned above, but also for the creation of junctions with special characteristics [507]. 

The formation of -aminodiphenylamine is supposed to be the key intermediate in the formation of a dark green precipitate at the electrode surface during continued electrolysis of acidic aniline solutions. This has been characterized as an oligomer of aniline, for example, as the octamer emeraldine formed by a cascade of head-to-tail condensations [38,39]. Nelson, however, explained it as a mixture of mainly quinhydrone with a small amount of benzidine salt [37]. Today the electropolymerization of aniline under strongly acidic conditions is intensively studied as an important way to form the conducting polymer polyaniline [40] (see Chapters 31 and 32). 

Figure 1 Cyclic voltammograms recorded at 50mV/s during the electropolymerization on a gold surface of 0.1 M aniline in 0.5 M sulphuric acid (a), and of the polyaniline film in the supporting electrolyte (0.5 M sulphuric acid) alone after polymerization (b).

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