Study on physical and electrostatic interactions of counterions in poly(perfluorosulfonic) acid matrix: Characterization of diffusion properties of membrane using radiotracers

Suresh, G.; Sodaye, S.; Scindia, Y.M.; Pandey, Ashok K.; Goswami, A.

doi:10.1016/j.electacta.2007.03.044

Cited by 15 publications

(23 citation statements)

References 35 publications

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“…However, no impact of these reticulations could be detected on the membrane properties because of the low carbon fraction involved. Finally, the chemical degradation of the membrane, reported as an unzipping process, was revealed by the thickness decrease and began at 900 h; this matched the platinum band formation. Even so, as the membrane was polluted by cations, both the diffusion of water and the ionic conductivity of the membrane were significantly reduced 52–57. Therefore, it could be not excluded that it involved higher kinetics of the chemical degradation of the membrane due to a peroxide radical attack.…”

Section: Discussionmentioning

confidence: 99%

Changes in the chemical structure and properties of a perfluorosulfonated acid membrane induced by fuel‐cell operation

Bas¹,

Flandin²,

Danerol³

et al. 2010

J of Applied Polymer Sci

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Changes in a perfluorosulfonated acid polymer membrane in membrane electrode assemblies were studied after different times under stationary conditions in fuel cells. A large series of characterizations demonstrated changes in the morphology, mechanical behavior, and thermal stability upon aging. Overall, the membrane evolution could be mainly attributed to both chemical degradation and cationic contamination. The reduction in the membrane thickness, detected by scanning electron microscopy, was ascribed to a radical unzipping mechanism and polymer chain erosion after 900 h in service. An additional monotonic decrease in the number of C tertiary F groups was observed even at 400 h. In parallel, membranes were cation-contaminated, and this led to drastic changes in the thermal and mechanical properties in the first stage of fuel-cell operation. The pollution cations were shown to have Lewis acid strengths close to 0.25 and thus strongly interacted with sulfonate anions of the membrane. The kinetic dependence of these membrane modifications and the influence of the platinum band were also examined.

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Section: Discussionmentioning

confidence: 99%

Changes in the chemical structure and properties of a perfluorosulfonated acid membrane induced by fuel‐cell operation

Bas¹,

Flandin²,

Danerol³

et al. 2010

J of Applied Polymer Sci

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show abstract

“…The general trend concludes that larger cationic radii induce lower countercation hydration energy, and lower the water content sorbed within the membrane 16–20. This results in a smaller hydrated ionic cluster16 and in a decrease in the water diffusion coefficient within the membrane 21–23. For example, the exchange of proton to cesium cation reduces the water content and the water diffusion by a factor four 19, 21, 23–25.…”

Section: Introductionmentioning

confidence: 92%

“…This results in a smaller hydrated ionic cluster16 and in a decrease in the water diffusion coefficient within the membrane 21–23. For example, the exchange of proton to cesium cation reduces the water content and the water diffusion by a factor four 19, 21, 23–25. More classical metallic contaminants lead to a smaller reduction of about 1.4.…”

Section: Introductionmentioning

confidence: 99%

Key counter ion parameters governing polluted nafion membrane properties

Bas

Reymond

Danerol

et al. 2009

J Polym Sci B Polym Phys

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Some properties of perfluorosulphonated ionomer membranes contaminated by a series of 10 counter ions were investigated by infrared spectroscopy (FTIR), thermogravimetric analysis coupled to mass spectroscopy (TG-MS), and dynamic mechanical spectrometry (DMA). Distinctive parameters were extracted and regarded as a function of the cations' properties. An optimum interaction between sulfonate group and cation was found for cations with Lewis Acid Strength (LAS) in the 0.2-0.3 range. This critical value is found to be the Lewis Basic Strength (LBS-SO À 3 ) of the sulfonate anion in Nafion membrane. Thermal stability analyses also point out the influence of this cation parameter on the polymer degradation process. Cations with LAS values lower than LBS-SO À 3 improve the thermal stability of the side chains while cations with LAS values higher than LBS-SO À 3 enhance the thermal degradation. Moreover, the temperature of the modulus drop increases with the LAS of the counter ion. For cations with values lower 0.5, the transition is attributed to the glass relaxation of the polymer while for cations showing LAS values higher than 0.5, the loss of stiffness originates from the polymer thermal degradation process. The overview of the experimental data allows the definition of calibration curves as a function of the cations' LAS.

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“…The wide-ranging applications of this membrane are due to its excellent properties, as can be good water ion exchange, high electrical conductivity, excellent thermal and chemical stability and low gas permeability. For that, a comprehensive study of the transport processes through this membrane is a very important issue [1][2][3]. This is the reason why one of the main subjects of this paper has been to contribute to the study of this transport by means of the analysis of process dependence on some physical parameters when a Nafion membrane is separating water and methanol-water solution.…”

Section: Introductionmentioning

confidence: 99%

Study of the activation energy for transport of water and methanol through a Nafion membrane

Godino

Barragán

Izquierdo

et al. 2009

Chemical Engineering Journal

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Study on physical and electrostatic interactions of counterions in poly(perfluorosulfonic) acid matrix: Characterization of diffusion properties of membrane using radiotracers

Cited by 15 publications

References 35 publications

Changes in the chemical structure and properties of a perfluorosulfonated acid membrane induced by fuel‐cell operation

Changes in the chemical structure and properties of a perfluorosulfonated acid membrane induced by fuel‐cell operation

Key counter ion parameters governing polluted nafion membrane properties

Study of the activation energy for transport of water and methanol through a Nafion membrane

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