Electropolymerization Method

Most laboratory setups employ a three-electrode potentiostated system to ensure effective potential control and to maximize the reproducibility of the polymerization process. The positioning of the auxiliary electrode is critical in that it determines the electrical field generated, which can influence the quality and evenness of the polymer deposited. The electrode system shown in Figure 2.2 includes a reference electrode. A two-electrode cell can also be used, usually with galvanostatic (constant current) electropolymerization methods, but care must be taken to avoid overoxidation of the PPy through poor control of the potential. 

A similar approach has been used to prepare PAn/PVA composites.73 In this case, the PVA is dip-coated using a DMSO solution, and the electropolymerization is initiated before the DMSO is completely removed. PAn has been electropolymer-ized74 onto a platinum electrode wrapped in an aromatic copolyamide. PAn-nafion composites can be prepared using the coating-electropolymerization method.75... 

Electropolymerization methods are already established for two purposes—the coating of polymer films onto electrodes and the electroinitiation of bulk polymerization. Future prospects are probably brighter for the use of these processes in new coating technology, both for protection of metallic surfaces and for designed modification of electrodes in the manner discussed earlier. 

Crayston and coworkers have shown that vinylpyridine complex 10 may be electropolymerized efficiently in DMSO to yield an orange, luminescent film [33,34]. The method is much more controllable than that used in the traditional electropolymerization method for vinylbipyridine [35] and vinylterpyridine complexes [36]. 

Electropolymerization method is one of the most interesting method to control the copolymer composition in molecular sequence or chain sequence, drastically. Accordingly, in the case that the property of the electropolymerized material is electro-conductive and insoluble, a heterolayer structure and/or a sloped structure with conducting polymers are constructed on the electrode. 

We develop the potential-programmed electropolymerization method for modulating the composition of conducting polymer composite thin films to the depth direction. In this study, nm-order compositional control of composite thin films of conducing polymer, the... 

Electrodeposition and electropolymerization methods are convenient direct procedures for preparing modifying layers. The thickness and frequently the permeation and charge transport characteristics of the polymer films can be controlled by the applied potential. Lack of knowledge of the precise structure of the electropolymerized or electrodeposited polymer films however represents a problem. 

Electrochemical polymerization provides a convenient approach to fabricate CNTs/CP nanocomposites [46-53], Using such a strategy, the morphology and properties of the nanocomposites can be controlled by the electropolymerization conditions, such as the applied potential or current density. Ajayan and co-workers have reported the electrochemical oxidation of aniline in H SO on the CNTs electrode to fabricate CNT/PANl composites [46]. Chen et al. fabricated CNT/PPy nanocomposites, the first example of anionic CNTs acting as the dopant of a CP [47]. Their results showed that PPy was xmiformly coated on the surface of individual CNTs by electrolysis at a low apphed potential for a short time, rendering them potential applications in nanoelectronic devices. Another kind of CNTs/CP composite nanostructures, e.g., CNTs as inorganic fillers in CP matrices [54] can be prepared by a template-directed electropolymerization method. (Figure 13.3)... 

The electropolymerization method of functional monomers has proved successful in many cases, in particular to incorporate various ligands and their metallic complexes, like salen [66,245], porphyrin [246], diphosphine [247], pyridine [71,80,248,249], crown ether [250,251], metallofullerene [252], tetraazacyclotetradecane [253], or Prussian blue type [254] in a conjugated organic material like PPy, PTh, or PANE Thick films are likely to be obtained provided that the polymer is redox active at the deposition potential due to this, Zotti et al. demonstrated that 5,5 -bis(3,4-(ethylenedioxy)thien-2-yl)-2,2 -bipyridine could be electropolymerized when complexed by iron and ruthenium, but not in the case of complexation by nickel or copper [71]. 

The electropolymerization of o-methoxyaniline in the presence of (+)-(lS)- or (-)-(ll )-CSA yields an optically active polyaniline derivative. The polymer shows intense CD bands as a film deposited on an electrode. The polymer is soluble in NMP, CHCI3, DMF, DMSO, and MeOH, and the polymer also showed CD absorption in a solution probably based on a chiral main-chain conformation such as a helix. A film made by spin-coating a mixture of polyaniline with CSA also showed strong CD absorptions, which may be based on a helical conformation of the main chain. The electropolymerization method has been applied to the synthesis of an optically active polypyrrole which may have a helical conformation. ... 

Choice of electropolymerization method. Usually the galvanostatic method is the first choice with a current density of I to 5 mA/cm. The total charge is usually 100 to 200 mC/cm. During the first electropolymerization the cell contents are closely observed in order to see color changes in solution close to the electrode surface. This means the presence of soluble oligomers. After polymerization the surface of the electrode should be visibly covered with the polymer layer. 

Thin films of POT have been obtained by the electropolymerization method on Sn02 F electrodes... 

Peng and co-authors developed a new electrochemical sensor combining a molecularly imprinted technique and an electropolymerization method. A molecularly imprinted polymer film was fabricated by electropolymerizing o-phenylenediamine in the presence of paracetamol after depositing carboxyl-functionalized multiwalled... 

PPy nanocomposites with WO3, Si02, Sn02 and Ta205 Electropolymerization method [53]... 

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