Diazonium cyclic voltammetry

The versatility of the method is founded on the possibility of grafting a variety of functionalised aryl groups. This allows the attachment of a wide spectrum of substances[60]. In 1992, a study by Delamar and co-workers [61] demonstrated that reduction of diazonium salts at carbon surfaces resulted in a strongly attached surface layer. They attributed this to covalent bond formation between the aryl radical and the carbon surface [61,62], One electron reduction of aryl diazonium salts at carbon electrodes leads to grafting of aryl groups to the surface. Acetonitrile is often used as the modification medium. Reduction of the diazonium salt can be achieved by cyclic voltammetry or controlled potential electrolysis. The coupling reaction is favored both by the adsorption of the diazonium prior to its reduction and by the relatively positive potential of the diazonium prior to its reduction[62],... 

Which is best for grafting diazonium salts chonoamperometry or cyclic voltammetry Cyclic voltammetry has been found to be more efficient during the grafting of thick nitrophenyl films. Potential sweeping was found to be essential to continuously desorb any physisorbed species that otherwise would clog the channels in the film and make it insulating [42],... 

It is possible to control the thickness of the polyphenylene Aims by controlling (i) the time duration of the reaction, (ii) the concentration of the diazonium salts, or (iii) the potential(s) of the electrolysis or cyclic voltammetry. The flrst two methods apply to spontaneous and chanical grafting, while all the three apply to electrografting. Using these parameters, monolayers have been attached to PPF for microelectronic applications. For example, a film of 7 PF-N=N-QH,-N02 groups has been obtained by electrochemical reduction (one cyclic voltammetry scan between -t-0.4 V and 0 V/ Ag/Ag+, scan rate v = 0.2 V s ) of the corresponding diazonium salt. A thickness of... 

The pioneering work of Delamar et al. [14] demonstrated the coating of glassy carbon by an organic layer of 4-nitrophenyl by the electrochemical reduction of (4-nitrophenyl)diazonium tetrafluoroborate (typical concentration 1-10 mM) from an ACN solution. Cyclic voltammetry shows two reduction phenomena in the first scan. The first peak centered at —0.04 V versus SCE is irreversible and corresponds to the diazonium reduction, whereas the second one is reversible and appears at a more cathodic potential (—1.20 V vs SCE) that is related to the electroactivity of the nitro group. A second voltammogram recorded on the same electrode shows... 

A first sign of the formation of an organic layer on metallic surfaces by electrochemical reduction of aryl diazonium salts is the disappearance of the expected characteristic broad and irreversible cathodic wave observed by cyclic voltammetry upon an initial scan towards negative potentials. Such blocking effect of the electrochemical response was firstly pointed out by Parker and coworkers.The different steps that take place along the electrografting process were established later on 17,371 been demonstrated that the electron transfer concerted with the loss of... 

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