Electrochemical characteristics conducting polymers

The electrochemical characteristics of an electroactive ion immobilized in a conducting polymer film depend on whether the film is conductive at the formal potential of the ion.243... 

As it logically follows from the considered mechanism and the existing experimental data, PANI-type conductive polymers can certainly be used to improve the characteristics of electrochemical capacitors. According to our estimations, a specific capacity of electrodes with conductive polymers could be increased by as much as to 3-5 times over that of the classical carbon electrodes. 

In this article we report the synthesis and electrochemical properties of the polymer derived from oxidation of X, poly(I), and the characteristics of a microelectrochemical transistor based on the polymer. Poly(I), which is formed by electrochemical oxidation of X, Equation 1, consists of a conducting polymer backbone, polythiophene. 

In this chapter we will attempt to provide a brief but illustrative description of the various aspects of the research and technology of conducting polymers. To appreciate fully the diverse range of operations that these materials may fulfil, it is crucial to understand their basic properties. Therefore, particular attention will be devoted here to the description of the mechanism of charge transport and to the characteristics of the electrodic processes in electrochemical cells. 

Electrochemistry in RTILs has recently been reviewed, and a book has been published on the topic. a large number of metals have been deposited from ionic liquids (Table 6.5) and a book has also been published on electrodeposition from these media. Alloys, semiconductors and conducting polymers have also been deposited from ionic liquids. The key advantages of ionic liquids for electrodeposition and electrochemical applications are their wide potential window, the high solubility of metal salts, the avoidance of water and their high conductivity compared to non-aqueous solvents. There are numerous parameters that can be varied to alter the deposition characteristics including temperature, the cation and anion used, diluents and additional electrolytes. ... 

Tables 6-9 give the device structures and performance metrics for monochromatic OLEDs that utilize organometallic emitters. Eigures 38-42 show the molecular structures for the various materials used in these devices. White OLEDs have also been prepared with these materials, but these will be discussed in a later section. Light-emitting electrochemical cells are treated in a separate section as well, since the finished devices have different operating characteristics than either of the other solution or vapor processed devices. Table 6 lists devices made solely with discrete molecular materials, while Table 7 gives data for devices made using polymeric materials. The only exception to the use of discrete molecular materials in Table 6 is for devices that use a conducting polymer, poly(3,4-ethylenedioxythiophene polystyrene sulfonate) (PEDOT), as a material to enhance the efficiency for hole injection into the organic layer. The mode of preparation for a given device is listed with the device parameters in the...

H.J. Lee and S.M. Park, Electrochemistry of conductive polymers. 30. Nanoscale measurements of doping distributions and current-voltage characteristics of electrochemically deposited polypyrrole films. J. Phys. Chem. B, 108, 1590 (2004). 

Table 14.1 gives an alphabetical listing of electrochemical sensors based on nanostructured conducting-polymer materials and composites. The main sensor characteristics have been extracted from the literature. The data given in the table are based on values extracted from the associated publications, either directly, or approximated from graphical data. The comments principally refer to abbreviations of the synthetic and deposition methods used, as well as other pertinent characteristics of the sensor. Responses or sensitivity values are based on either single data or slopes determined from calibrations. Detection limits are either formal limits of detection, or the lowest concentrations determined in the work, and... 

The electrochemical synthetic techniques of nanostructured conducting polymers are mainly carried out using galvanostat, potentiostat, and cyclic voltammetry (CV)- The advantages of electrochemical over chemical preparation are that the sizes of the nano-particles are easily controlled by the applied potential, current density, scan rate, and the number of cycles, and especially that the nanostmctured conducting polymer deposited on the electrode material can be directly used to investigate its electrochemical properties and in situ spectroelectrochemical characteristics. 

If species Z is present in large excess compared to O, then (17.2) is a pseudo-first-order reaction. To compare conveniently catalytic activity between the nanostructured conducting polymer and the bulk polymer, the key thing is that the amounts of the conducting polymer deposited on the electrode should be equal. The characteristics of the electro-catalytic reaction are related to the electrochemical techniques used. These characteristics are an increase in current density for potentiostat a shift in peak potentials for oxidation and reduction toward less positive potentials and more positive potentials, respectively, for galvanostat and an increase in the oxidation or reduction peak current, or a shift of the peak potentials of oxidation and reduction toward less positive potentials and more positive potentials, respectively, or both for cyclic voltammetry. 

The unique transport characteristics of conducting polymer membranes that we have demonstrated arise from their electrochemical properties. For the purpose of this discussion polypyrroles will be used, however, similar principles apply to transport across polyaniline membranes. 

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