Poly electrochemical properties

Here we introduce a personal point of view about the interactions between conducting polymers and electrochemistry their synthesis, electrochemical properties, and electrochemical applications. Conducting polymers are new materials that were developed in the late 1970s as intrinsically electronic conductors at the molecular level. Ideal monodimensional chains of poly acetylene, polypyrrole, polythiophene, etc. can be seen in Fig. 1. One of the most fascinating aspects of these polymeric... 

Platinum electrodes are made usually from poly crystalline metal the crystal planes at the surface include both the (111) and (100) faces in approximately equal proportions. The electrochemical properties of Pt(lll) and Pt(100) faces are not identical. (Generally, the physical properties of individual metal crystal faces, such as work function, catalytic activity, etc., are different.)... 

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. 

Electrochemical oxidation of X produces a polymer film with polythiophene as the backbone and viologen centers as pendant redox groups. The electrochemical properties of the polymer are the combination of polythiophene and viologen. Using viologen subunits as the internal standard (one per repeat unit of the polymer), the "doping level" of the oxidized polythiophene backbone at its maximum conductivity can be measured and is about 25%. The charge transport via the pendant V2+/+ of poly(l) has been studied by... 

Intensive effort has been devoted to the optimization of CCP structures for improved fluorescence output of CCP-based FRET assays. The inherent optoelectronic properties of CCPs make PET one of the most detrimental processes for FRET. Before considering the parameters in the Forster equation, it is of primary concern to reduce the probability of PET. As the competition between FRET and PET is mainly determined by the energy level alignment between donor and acceptor, it can be minimized by careful choice of CCP and C. A series of cationic poly(fluorene-co-phenylene) (PFP) derivatives (IBr, 9, 10 and 11, chemical structures in Scheme 8) was synthesized to fine-tune the donor/acceptor energy levels for improved FRET [70]. FI or Tex Red (TR) labeled ssDNAg (5 -ATC TTG ACT ATG TGG GTG CT-3 ) were chosen as the energy acceptor. The emission spectra of IBr, 9, 10 and 11 are similar in shape with emission maxima at 415, 410, 414 and 410 nm, respectively. The overlap between the emission of these polymers and the absorption of FI or TR is thus similar. Their electrochemical properties were determined by cyclic voltammetry experiments. The calculated HOMO and LUMO... 

The formed thin and uniform poly(phenyleneoxide) films on electrode are interesting because of their electric and electrochemical properties. Figure 1 shows a typical cyclic voltammogram for the oxidation of 2,6-dimethylphenol at a platinum electrode in... 

Kim, Y. S., Dong, L., Hickner, M. A., Glass, T. E., Webb, V. and McGrath, J. E. 2003. State of water in disulfonated poly(arylene ether sulfone) copolymers and a perfluorosulfonic acid copolymer (Nafion) and its effect on physical and electrochemical properties. Macromolecules 36 6281-6285. 

As described earlier, the choice of bisphenols for the polymerization of poly(arylene ether ketone)s is large. In particular, the electrochemical properties of the above monomer copolymerized with bisphenol AF were studied. The fundamental PEM characteristics (water uptake and conductivity) were analogous to those of the BPSH systems for a given lEC. 

Abstract This review describes recent results in the field of poly(aryleneethynylene)s (PAEs) that contain metal ions in the polymer backbone, or in the polymer side chain. This work is focused primarily on polymers possessing ligands of metal complexes as part of the aryle-neethynylene chain. PAEs with porphyrinylene in the backbone have also been addressed. Synthetic routes toward the polymers, as well as their photochemical, photophysical, and electrochemical properties, are presented. Monodisperse oligo(phenyleneethynylene)s with terminal metal complexes or with a ferrocene and thiol at each end are mentioned. 

A poly(phenylquinoxaline) was prepared for electroluminescence applications <1996SM(76)105>. Crystallization of solution donor-acceptor complexes of 2,3-dimethylquinoxaline 1,4-dioxide or phenazine 5,10-dioxide with TCNE afforded two-component solids containing weakly bound 1-D donor-acceptor arrays <1997TL7665>. A pyrazine ladder polymer was constructed from two different pyrazine units, as an optical device <1999JA8783>. The new electron-deficient macrocycle tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine was prepared from l,2-di(2-pyridyl)ethanedione and 2,3-diaminomaleonitrile for a study of its electrochemical properties <2004IC8626>. 

In the most important series of polymers of this type, the metallotetraphenylporphyrins, a metalloporphyrin ring bears four substituted phenylene groups X, as is shown in 7.19. The metals M in the structure are typically iron, cobalt, or nickel cations, and the substituents on the phenylene groups include -NH2, -NR2, and -OH. These polymers are generally insoluble. Some have been prepared by electro-oxidative polymerizations in the form of electroactive films on electrode surfaces.79 The cobalt-metallated polymer is of particular interest since it is an electrocatalyst for the reduction of dioxygen. Films of poly(trisbipyridine)-metal complexes also have interesting electrochemical properties, in particular electrochromism and electrical conductivity.78 The closely related polymer, poly(2-vinylpyridine), also forms metal complexes, for example with copper(II) chloride.80... 

MWCNTs were functionalized with iron phthalocyanines (FePc) to improve the sensitivity towards hydrogen peroxide. A highly sensitive glucose sensor with an FePc-MWCNT electrode based on the immobilization of GOx on poly(o-amino-phenol) (POAP)-electropolymerized electrode surface [219]. A hemin-modified MWCNT electrode to be used as a novel 02 sensor was obtained by adsorption of hemin at MWCNTs and the electrochemical properties of the electrode were characterized by cyclic voltammetry [220]. 

As with all supramolecular structures, one of the most important issues is whether a direct relationship between the structure of a material and its function or properties can be established. In the following, some examples of polymer systems which show such a correlation will be discussed. The materials addressed will include block copolymers, polyalkylthiophenes and a multilayer system based on the self-assembly of polyelectrolytes. Detailed studies on the electrochemical properties of redox-active polymers, based on poly(vinyl pyridine) modified with pendent osmium polypyridyl moieties, have shown that electrochemical, neutron reflectivity and electrochemical quartz crystal microbalance measurements can yield detailed information about the structural aspects of thin layers of these materials. 

However, it seems likely that a conductivity value of 10 S cm at room temperature is a goal that can only be achieved with polymer networks including organic solvents as plasticizers [96] or with polymer matrixes like polyacrylonitrile [97] or poly(methyl methacrylate) [98] entrapping a large amount of organic electrolytic solution, i.e., with hybrid and/or gel electrolytes. These electrolytes combine the advantage of the polymer s mechanical properties with the electrochemical properties of the liquid electrolytes. 

Electronically conducting polymers (ECPs) such as polyaniline (PANI), pol3T5yrrole (PPy) and poly(3,4-ethylenedioxjdhiophene) (PEDOT) have been applied in supercapacitors, due to their excellent electrochemical properties and lower cost than other ECPs. We demonstrated that multi-walled carbon nanotubes (CNTs) prepared by cataljdic decomposition of acetylene in a solid solution are very effective conductivity additives in composite materials based on ECPs. In this paper, we show that a successful application of ECPs in supercapacitor technologies could be possible only in an asymmetric configuration, i.e. with electrodes of different nature. 

Various para substituted poly-N-arylpyrrole polymer films were prepared and their electrochemical properties were measured. Of particular interest are the poly-N-p-nitrophenylpyrrole films which can be oxidized to produce the polypyrrole cation and reduced to produce the nitrophenyl anion. The polymer films can be repeatedly switched between the neutral, cationic and anionic forms with coulombic reversibility and with little ir-interaction between the pyrrole and the aryl ring. 

Efforts to stabilize BLMs by the use of polymerizable lipids have been successful, but the electrochemical properties of these membranes were greatly compromised and ion channel phenomena could not be observed [21]. Microfiltration and polycarbonate filters, polyimide mesh, and hydrated gels have been used successfully as stabilizing supports for the formation of black lipid films [22-25] and these systems were observed to retain their electrical and permeability characteristics [24]. Poly(octadec-l-ene-maleic anhydride) (PA-18) was found to be an excellent intermediate layer for interfacing phospholipids onto solid substrates, and is sufficiently hydrophilic to retain water for unimpeded ion transfer at the electrode-PA-18 interface [26]. Hydrostatic stabilization of solventless BLMs has been achieved by the transfer of two lipid monolayers onto the aperture of a closed cell compartment however, the use of a system for automatic digital control of the transmembrane pressure difference was necessary [27]. 

Bondarev SL, Bachilo SM, Dvornikov SS and Tikhomorov SA (1989) 2 - So fluorescence and transient S Sq absorption ofo//-tm s-/3-carotenein solid and liquid solutions. Photochem Photobiol, A Chemistry 46 315-322 Bouwman W, Jones A, Phillips D, Thibodeau P, Friel C and Christensen R (1990) Fluorescence of gaseous tetraenes and pentaenes. J Phys Chem 94 7429-7434 Bredas JL, Sdbey R, Boudreaux DS and Chance RR (1983) Chain-length dependence of electronic and electrochemical properties of conjugated systems Polyacetylene, polyphenylene, polythiophene, and poly pyrrole. J Am Chem Soc 105 6555-6559... 

The electrochemical behavior of poly(RCOT)s has also been examined [40]. As expected from the electrochemical properties of unsubstituted polyacetylene, films of poly(RCOT)s coated on an electrode and immersed in an acetonitrile electrolyte solution (in which the polymers are not soluble) are found to undergo reversible oxidative and reductive doping. Unlike unsubstituted polyacetylene, these films may be prepared readily by casting from solution, or, in the case of poly(scc-butylCOT), by electrodecomposition from a THF solution. In contrast to the voltammetry of polymer films, cyclic voltammograms of methylene chloride... 

Through use of an alternative hydrolytic approach, poly(ferrocenylalkoxysilanes) have also been incorporated into gels and oxide matrices by means of sol-gel chemistry. For example, poly(ferrocenylalkoxysilanes) 76 (R = R = OMe, OTr, or OGH2Ph) were hydrolyzed in water using fluoride catalysts to afford orange, insoluble solids in which the electrochemical properties of the ferrocene units were conserved. " ... 

Bertoncello R, Notargiacomo A., Riley D. J., Ram M. K., and Nicolini C., Preparation, characterization and electrochemical properties of Nafion doped poly(ortho-anisidine) Langmuir-Schaefer films, Electrochem. Commun., 5(9), 787-792, 2003. 

PANI-NFA 2O5 is promising nanocomposite material for utilization as a cathode for ion-Li batteries [292,293]. PANI-NFs have been used as a cathode material for rechargeable Li-polymer cells assembled with a gel polymer electrolyte [152], and in an aqueous PANI-Zn rechargeable battery [261]. Dispersions of dedoped PANI-NFs in poly(vinyhdene fluoride-hexafluoropropylene)-based gel polymers can be used as electrolyte membranes for rechargeable Li batteries [513]. PANI-NF and PANI-NT arrays, which show superior electrochemical properties to the bulk counterpart, can be applied to Li-polymer thin-film batteries, which are shape-flexible and specifically suitable for powering integrated circuit cards and microelectromechanical systems [514,515]. 

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