Charge-transfer reactions in pendant viologen polymers coated on graphite electrodes and at electrode/pendant viologen polymer film interfaces

Oyama, Noboru; Ohsaka, Takeo; Yamamoto, Hisao; Kaneko, Masao

doi:10.1021/j100407a065

Cited by 70 publications

(21 citation statements)

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“…A first analysis of this phenomenon supports the view that the conductivity of this material-especially of the hexathiophene segments-results from hopping processes [20][21][22] within mixed valence states. Hexathiophenes are interpreted as the oligomeric analoga of polythiophenes.…”

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confidence: 62%

Electrochemically Induced Formation of Independent Conductivity Regimes in Polymeric Tetraphenylbenzidine Systems

2010

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[a] p-Conjugated organic polymers have gained increasing interest since their discovery because of their ability to become electrically conducting upon doping.[1] The understanding of the mechanism of conductivity in these materials is highly important both from a fundamental point of view [2] and for their applications in devices. [3][4][5] Conjugated polymers are nonconducting in the neutral state and conducting in the charged state. Electrochemical studies coupled with conductance measurements of conjugated polymers typically show conductivities over large potential ranges. [6,7] In the literature several models exist to describe the conductivity mechanism in conjugated polymers. [8][9][10][11] Probably the most established in the electrochemical literature is the bipolaron model, which is derived from solid-state materials and based on the band model. [9,12,13] Different aspects of this model are discussed in the literature. Upon increasing the oxidation level, first polarons (radical cations) and then bipolarons (dications) are formed. The bipolaron model explains conductivity in conjugated polymers with the transport of first locally stabilized polarons followed by transport of bipolarons. According to theoretical predictions, the broadening of the bipolaron states produces new unfilled valence bands and leads to metal-like conduction at high doping levels. A characteristic sigmoidal shape of conductivity as function of charging and the disappearance of the ESR signal at high charging support this view involving the transport of spinless bipolaronic charge carriers and not of electrons.[14] However, some experiments reveal a decrease of the conductivity after reaching the plateau at high doping levels, [6,[15][16][17] which cannot be unambiguously explained by a simple bipolaron conduction in conjugated polymers. Different explanations have been presented in the literature, for example, mixed valence exchange processes between polaron and neutral or polaron and bipolaron sites. [16,18] Wrighton reports that at high charging levels the decrease in conductivity can be attributed to localization of charges on the chains.[6] Very recently, Heinze et al. studied 3D hybrid networks consisting of dendritic cores of polyphenylene systems and hexathiophene oligomers crosslinking the dendritic cores.[19] Surprisingly, cyclic voltammetry coupled with in situ conductance measurements showed two independent regimes of conductivity which can be attributed to the hexathiophene oligomers and polyphenylene cores, respectively. A first analysis of this phenomenon supports the view that the conductivity of this material-especially of the hexathiophene segments-results from hopping processes [20][21][22] within mixed valence states. Hexathiophenes are interpreted as the oligomeric analoga of polythiophenes. Fichou and Garnier reported formation of polarons and bipolarons upon increased doping level by spectroscopic evidence.[23] However, no experimental data on the conductivity were shown that might have confirmed the bipo...

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confidence: 62%

Electrochemically Induced Formation of Independent Conductivity Regimes in Polymeric Tetraphenylbenzidine Systems

2010

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“…Simultaneous electrochemical detection of UA and AA at a poly(N,N-dimethylaniline) film coated GC electrode (PDMA/GCE) was discussed by Roy et al [85]. The PDMA polymer film was electrodeposited onto a polished glassy carbon electrode from a 0.1 mol L À1 DMA in 0.5 mol L À1 Na 2 SO 4 + H 2 SO 4 solution (pH 1.0) by sweeping the potential between À0.2 to 1.5 V at 50 mV s À1 for 1 h following reported procedures [86][87][88][89][90][91][92][93]. The resulting PDMA film-coated electrodes conferred anti-fouling properties and shown a stable and reproducible electrochemical response to UA without any interference.…”

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confidence: 99%

Electrochemical Detection of Uric Acid in Mixed and Clinical Samples: A Review

et al. 2011

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The present review has sought to explore the technological advances that have been made in recent years towards the selective analysis of uric acid and critically evaluate how they could, in fact, be exploited as a basis for a multi analyte sensor incorporating uric acid detection. Numerous strategies have evolved in recent years but these have invariably focused on the manufacture and response characterization of discrete sensors. Various methods of obtaining selective detection such as use of uricase enzymes, nanoparticles, carbon nanotubes, polymers, conducting polymers and MIPs are also discussed along with the clinical relevance of UA determination.

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“…Contrary to the change expected from electron-hopping transport, several groups have reported decreases in D with increased loading [2,28,29]. These decreases have been ascribed to the effect of electrostatic cross-linking between incorporated redox ions and oppositely charged polymer lattices, or to the ion-transfer rate limited by a decreasing residence site [25,30].…”

Section: Potential-step Chronoamperometrymentioning

confidence: 94%

Electrochemical Study of the Binding Interaction Between Dihydroxybenzenesulfonates and Viologen-Linked Polypyrrole

et al. 2002

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Charge-transfer reactions in pendant viologen polymers coated on graphite electrodes and at electrode/pendant viologen polymer film interfaces

Cited by 70 publications

References 0 publications

Electrochemically Induced Formation of Independent Conductivity Regimes in Polymeric Tetraphenylbenzidine Systems

Electrochemically Induced Formation of Independent Conductivity Regimes in Polymeric Tetraphenylbenzidine Systems

Electrochemical Detection of Uric Acid in Mixed and Clinical Samples: A Review

Electrochemical Study of the Binding Interaction Between Dihydroxybenzenesulfonates and Viologen-Linked Polypyrrole

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