Polymer films on electrodes. 8. Investigation of charge-transport mechanisms in Nafion polymer modified electrodes

White, Henry S.; Leddy, Johna; Bard, Allen J.

doi:10.1021/ja00382a013

Cited by 364 publications

(222 citation statements)

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“…Nafion ® LS films can preconcentrate electroactive cations and such a process is faster than at electrodes coated with recasted Nafion ® films. The electroactivity of incorporated Ru[(NH 3 ) 6 ] 3+ at relatively high scan rates (> 40 mV s -1 ) is ruled by a very small apparent diffusion coefficient which indicates charge transport phenomena slower than in recasted films. However, the amplification of signals related to the analyte incorporation in the coating still prevails so allowing one to use Nafion ® LS coated electrodes for the preconcentration and ion-exchange voltammetric determination of electroactive cations present at micromolar solution concentrations.…”

Section: Discussionmentioning

confidence: 97%

“…15 In the present work we examine in detail the charge transfer and diffusion behavior of electroactive probe based on cations such as Ru[(NH 3 ) 6 ] 3+ , incorporated by ion-exchange in Nafion ® LS films deposited on electrode surfaces in comparison with "traditional" coatings deposited by solvent evaporation of recasted Nafion ® solutions. 3,4,18 …”

Section: Introductionmentioning

confidence: 99%

“…It is used as ionomeric permselective membrane for a variety of electrochemical applications including fuel cells, water electrolyzers and chlor-alkali cells, 1,2 chemically modified electrodes, [3][4][5] ion-selective and potentiometric sensors, [6][7] voltammetric sensors [8][9] and electrochromic devices. [10][11] For electroanalytical purposes, Nafion ® coated electrodes has been prepared mainly by depositing a film of the polymer recasted from water-alcohol solutions.…”

Section: Introductionmentioning

confidence: 99%

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Preparation and voltammetric characterization of electrodes coated with Langmuir-Schaefer ultrathin films of Nafion®

Bertoncello¹,

Ugo²

2003

J. Braz. Chem. Soc.

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Filmes ultrafinos do polímero perfluorado Nafion ® foram depositados em eletrodos de óxido índio-titânio (ITO) usando a técnica de Langmuir-Scaefer (LS), depois da otimização das condições de composição da subfase. As características morfológicas das camadas foram obtidas por Microscopia de Força Atômica (AFM). Filmes de Nafion ® LS mostraram boa uniformidade e cobertura completa da superfície do eletrodo. No entanto, diferentes graus de organização das camadas poliméricas ficaram evidentes com respeito a filmes finos depositados por revestimento rotacional. Eletrodos ITO modificados com camadas de Nafion ® LS, pré-concentrados por cátions eletroativos de troca iônica, como o Ru[(NH 3 ) 6 ] 3+ , dissolveram-se em soluções diluídas. A espécie eletroativa foi retida pelo ITO com camada de Nafion ® LS, mesmo depois da mudança do eletrodo modificado para eletrodo de suporte purificado. Isto possibilitou o uso do complexo de rutênio como padrão voltamétrico para o teste do fenômeno de difusão nos filmes de Nafion ® LS. Os coeficientes de difusão aparentes (D app ) do Ru[(NH 3 ) 6 ] 3+ incorporado no filme de Nafion ® LS foram obtidos por medidas voltamétricas. Os valores de D app diminuíram levemente com o aumento da quantidade de complexo de rutênio incorporado no filme ultrafino e foram significativamente mais baixos do que os valores para filmes de Nafion ® recapados, em acordo com a natureza altamente condensada dos filmes de Nafion ® LS.Ultrathin films of Nafion ® perfluorinated polymer were deposited on indium-tin oxide electrodes (ITO) by using Langmuir-Schaefer (LS) technique, after optimization of the subphase composition conditions. Morphological characteristics of these coatings were obtained by Atomic Force Microscopy (AFM). Nafion ® LS films showed a good uniformity and complete coverage of the electrode surface, however a different organization degree of the polymer layer was evidenced with respect to thin films deposited by spin-coating. ITO electrodes modified with Nafion ® LS coatings preconcentrate by ion-exchange electroactive cations, such as Ru[(NH 3 ) 6 ] 3+ , dissolved in diluted solutions. The electroactive species is retained by the Nafion ® LS coated ITO also after transfer of the modified electrode into pure supporting electrolyte. This allowed the use of the ruthenium complex as voltammetric probe to test diffusion phenomena within the Nafion ® LS films. Apparent diffusion coefficients (D app ) of Ru[(NH 3 ) 6 ] 3+ incorporated in Nafion ® LS films were obtained by voltammetric measurements. D app values decrease slightly by increasing the amount of ruthenium complex incorporated in the ultrathin film. They are significantly lower than values typical for recasted Nafion ® films, in agreement with the highly condensed nature of the Nafion ® LS fims.Keywords: Langmuir-Schaefer films, Nafion ® , modified electrodes, Ru[(NH 3 ) 6 ] 3+ , diffusion coefficients IntroductionNafion ® , a copolymer of tetrafluoroethylene and sulfonyl fluoride vinyl ether, is one of the most interesting solid polyme...

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Preparation and voltammetric characterization of electrodes coated with Langmuir-Schaefer ultrathin films of Nafion®

Bertoncello¹,

Ugo²

2003

J. Braz. Chem. Soc.

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“…While these and other studies (2)(3)(4)(5)(6) clearly show that hydrophobic interactions can play a role in determining the strength of the Nafion/counterion interaction, structural and charge differences in the counterions used made quantitative conclusions about the contribution of the hydrophobic effect difficult. Furthermore, the electrochemical isotherm method used (1,7) is extremely tedious and time consuming.…”

Section: Introductionmentioning

confidence: 99%

High-performance liquid chromatographic studies of the ion-exchange selectivity of Nafion

Moore¹,

Wilkerson²,

Martin³

1984

Anal. Chem.

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“…[60][61][62][63][64][65][66][67][68][69][70][71][72][73] The most popular cation exchanging system is Nafion  , although poly(styrene sulphonate), poly(vinyl sulphate), deprotonated poly(acrylic acid) and poly(-L-lysine), Tosflex, poly(vinylpyridine) and cellulose acetate have received significant attention. [73][74][75][76][77][78][79][80][81][82][83][84][85][86] In addition, the preconcentrating agent also may acts as a permeselective coating, offering selectivity by exclusion from the surface of unwanted matrix constituents, while allowing transport of the target analyte. Pratical examples are obtained by use of size-exclusion coatings such as poly(diaminobenzene), 87 hydrophobic lipid 88 or charged-exclusion ionomeric Nafion coatings.…”

Section: Chemically Modified Electrodesmentioning

confidence: 99%

Electrochemical sensors: a powerful tool in analytical chemistry

Stradiotto¹,

Yamanaka²,

Zanoni³

2003

J. Braz. Chem. Soc.

325

160

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Sensores potenciométricos, amperométricos e condutométricos são sensores eletroquímicos com imensa aplicação nas áreas de meio ambiente, indústria e análises clínicas. O presente trabalho apresenta uma revisão generalizada dos aspectos fundamentais, os desenvolvimento e a contribuição destes sensores na área de química analítica, e reporta alguns aspectos relevantes dos avanços na área de sensores eletroquímicos no Brasil.Potentiometric, amperometric and conductometric electrochemical sensors have found a number of interesting applications in the areas of environmental, industrial, and clinical analyses. This review presents a general overview of the three main types of electrochemical sensors, describing fundamental aspects, developments and their contribution to the area of analytical chemistry, relating relevant aspects of the development of electrochemical sensors in Brazil.

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Polymer films on electrodes. 8. Investigation of charge-transport mechanisms in Nafion polymer modified electrodes

Cited by 364 publications

References 0 publications

Preparation and voltammetric characterization of electrodes coated with Langmuir-Schaefer ultrathin films of Nafion®

Preparation and voltammetric characterization of electrodes coated with Langmuir-Schaefer ultrathin films of Nafion®

High-performance liquid chromatographic studies of the ion-exchange selectivity of Nafion

Electrochemical sensors: a powerful tool in analytical chemistry

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