Fabrication and physico-chemical properties of Nafion Langmuir–Schaefer films

Bertoncello, Paolo; Ram, Manoj K.; Notargiacomo, A.; Ugo, Paolo; Nicolini, Claudio

doi:10.1039/b202449g

Cited by 47 publications

(68 citation statements)

References 57 publications

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“…These transformations were previously put in evidence by Brewster Angle Microscopy. 11 The comparison of the different isotherms shown in Figure 1, indicates that the degree of condensation of the film depends on the specific interactions between Nafion ® and the cations dissolved in the subphase. In particular, the evidence that the condensation extent follows the sequence Na + >H + >Li + indicates a correlation with the sequence reported in the literature for the ion-exchange selectivity of Nafion ® for these ions.…”

Section: Resultsmentioning

confidence: 99%

“…Preparation and optimization of these subphases was described elsewhere. 11 A large number of deposition parameters influences the microstructure and the growth rate of the Nafion ® LS film. Based on Langmuir behavior, the conditions of parameters used for the deposition are: surface pressure of 25 mN m -1 and 0.1 mol dm -3 NaCl solution as the subphase.…”

Section: Methodsmentioning

confidence: 99%

“…16 In a recent paper, 11 we showed that by choosing proper composition of the subphase it was possible to obtain Langmuir monolayers of Nafion ® at the water/air interface and that this films can be deposited on solid substrates by LS technique. At variance with "classical" LB technique, in the LS deposition the substrate is placed horizontally (instead of vertically) in contact with the Langmuir monolayer film.…”

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. 8 Such J. Braz.…”

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: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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“…The substrate touches the monolayer horizontally, than it is inclined and moved up. Although the LS technique showed to work well for Nafion ® [15], it has the limitation to rely upon the manual ability and experience of the experimentalist. In the present work we focus on the possibility to deposit Langmuir layers of ionomers by resorting to the Langmuir-Blodgett technique which is a vertical dipping-lift deposition technique for which the rate and extent of the movement of the substrate through the interfacial film is controlled automatically by using a mechanical dipper driven by suitable software.…”

Section: Introductionmentioning

confidence: 99%

Langmuir–Blodgett films of different ionomeric polymers deposited on electrode surfaces

Ugo

Bertoncello

Vezzà

2004

Electrochimica Acta

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This paper shows the possibility to apply the Langmuir-Blodgett (LB) techniques for the preparation of ultrathin films of various ionomeric polymers, namely Nafion ® (perfluorinated cation-exchanger), Tosflex ® (perfluorinated anion-exchanger) and Eastman AQ55 ® (polyestersulfonated cation-exchanger). The pressure-area isotherms and the condensation degree of the interfacial films depend on the chemical structure of the ionomer and on the nature of the electrolyte dissolved in the subphase. The addition of a strong electrolyte to the subphase is, in fact, a compulsory requirement in order to allow the formation of a stable ionomer layer at the air-water interface. The interfacial film can be transferred by LB deposition technique onto substrates such as glassy carbon, gold or indium-tin oxide electrodes. Quartz crystal microbalance data indicate the uniformity of such LB-coatings and ion-exchange voltammetric measurements confirm their ion-exchange preconcentration capabilities. Films based on perfluorinated ionomers such as Nafion ® and Tosflex ® are characterized by higher condensation degrees and are closer to reach a monolayer packing than films based on the polyestersulfonated Eastman AQ55 ® .

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Ionomer-Coated Electrodes and Nanoelectrode Ensembles as Electrochemical Environmental Sensors: Recent Advances and Prospects

2002

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Fabrication and physico-chemical properties of Nafion Langmuir–Schaefer films

Cited by 47 publications

References 57 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®

Langmuir–Blodgett films of different ionomeric polymers deposited on electrode surfaces

Ionomer-Coated Electrodes and Nanoelectrode Ensembles as Electrochemical Environmental Sensors: Recent Advances and Prospects

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