Hybridization of Nafion membranes by the infusion of functionalized siloxane precursors

Lavorgna, Marino; Mascia, L.; Mensitieri, Giuseppe; Gilbert, Marianne; Scherillo, Giuseppe; Palomba, Biagio

doi:10.1016/j.memsci.2007.02.032

Cited by 47 publications

(25 citation statements)

References 33 publications

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“…The test cell design makes it possible to measure the conductivity of the membrane in the plane by minimizing resistance at the interface between electrodes and membrane (i.e., impedance measurements at four electrodes method) [27]. The MCTC cell was connected both to an electrochemical workstation, consisting of a potentiostat and a frequency response analyzer (Solartron SI 1280B) and a Gas Delivery System (BekkTech Company) which provided nitrogen flow at controlled humidity.…”

Section: Water Liquid Uptake Water Vapor Sorption Proton Conductivimentioning

confidence: 99%

“…The absorbance band at 1,200 cm -1 , assigned to the asymmetric stretching mode of -CF 2 -groups is used as internal standard in order to make the spectrum comparison more effective [27]. Although, the major vibrational features of neat Nafion polymer are well observed in the spectrum of the composite membrane, it is worth noting that the zeolite filler increases the absorbance intensity of bands at around 1,080 and 940 cm -1 .…”

Section: Chemical and Morphological Characterization Of Nafionzeolitementioning

confidence: 99%

“…This unexpected result may be ascribed to the poor dispersion of the filler which causes a significant membrane swelling in liquid water (see Table 1). Thus, the average separation distance between hydrophilic and hydrophobic domains increases, as shown by SAXS analysis, and this has a negative affect on the proton transport mechanism [27,52]. Table 2 lists for the swollen membranes, the values of the proton conductivity, the methanol crossover and the corresponding selectivity (calculated by dividing the proton conductivity by the methanol permeability).…”

Section: Proton Conductivity and Methanol Crossovermentioning

confidence: 99%

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Transport Properties of Zeolite Na‐X–Nafion Membranes: Effect of Zeolite Loadings and Particle Size

Lavorgna¹,

Sansone²,

Scherillo³

et al. 2011

Fuel Cells

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Na-X zeolites particles, synthesized in two size ranges,\ud namely 200–300 nm and 30–100 nm, were used to prepare\ud Nafion/Na-X zeolite composite membranes by recast\ud method. The physical, chemical, and morphological properties\ud of the zeolite powders and composite membranes were\ud examined by XRD, N2 adsorption isotherms, FTIR, SEM,\ud and SAXS analysis. Furthermore, the effect of zeolite particles\ud size and loadings (i.e., 5 and 10% w/w) on the water,\ud methanol, and proton transport properties was investigated.\ud It has been found that the size of the Na-X zeolite particles\ud plays a key role in the proton and methanol transport\ud behavior since it rules the zeolite hydrophilic behavior, the\ud morphology of polymer–filler interphase, and also the nature\ud of water established in the composite membrane.\ud The results show that the membranes loaded with a 5%\ud w/w of submicron-sized Na-X zeolite exhibit a proton conductivity\ud and selectivity significantly higher than Nafion. In\ud particular the proton conductivity at 120 °C is around eight\ud times and the selectivity at 25 °C is around 40% higher than\ud those exhibited by recast Nafion

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Section: Water Liquid Uptake Water Vapor Sorption Proton Conductivimentioning

confidence: 99%

Section: Chemical and Morphological Characterization Of Nafionzeolitementioning

confidence: 99%

Section: Proton Conductivity and Methanol Crossovermentioning

confidence: 99%

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Transport Properties of Zeolite Na‐X–Nafion Membranes: Effect of Zeolite Loadings and Particle Size

Lavorgna¹,

Sansone²,

Scherillo³

et al. 2011

Fuel Cells

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“…The polymer can contain a proton-donor group (so-called ionomers, the most used of which is Nafion) [13,27,29,30,37,62,69,[87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103], or it is introduced into the polymer by the appropriate reactions during the formation of the PEM [36,56,[104][105][106][107]. In addition the ionomer was synthesized from the corresponding monomers in the sol-gel process [106][107][108][109][110][111]; this is discussed in a separate section.…”

Section: Organic-inorganic Hybrid Proton-exchange Membranes Includingmentioning

confidence: 99%

“…The temperature dependence of the conductivities of systems where the proton transfer is due to segmental motion of the polymer chains is described by the Vogel-Tamman-Fulcher equation [32,41,49,[52][53][54]67]. In other cases the temperature dependence of the PEMs obeys the Arrhenius equation [8,36,49,62,[68][69][70].…”

Section: Introductionmentioning

confidence: 99%

Polymeric organic–inorganic proton-exchange membranes for fuel cells produced by the sol–gel method

2011

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Approaches to the production of polymeric organic-inorganic hybrid proton-exchange membranes for fuel cells by the sol-gel method are summarized, and a classification is proposed for them. Features of the mechanism of conduction in the proton-conducting membranes are considered. Characteristics of the hybrid membranes and of fuel cells using them are presented. The main directions of research in this field are discussed.

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Nanostructured Polymer Composites by Sol–Gel Method

Mascia

Lavorgna

2012

Wiley Encyclopedia of Composites

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The sol‐gel method for producing polymer nanocomposites is discussed in general terms and also with reference to modification of membranes, enhancing the performance of conventional composites and improving the properties of coatings. The modification of proton exchange membranes (Nafion types) has been made via two different routes, one involving the infusion of the silane precursors into an existing swollen membrane and the other where a new membrane is cast from a solution mixture of Nafion and a silane precursor. Further improvements in the performance of the silica‐modified Nafion membranes have been achieved through the introduction of SO 3 H groups in the siloxane domains. The silica modification of ion permeation membranes is discussed with reference to solid polyelectrolytes, whereas for gas separation membranes the emphasis has been placed on aspects related to both Henry's dissolution and Langmuir sorption arising from the mesoporosity of the siloxane domains. The improvements in performance of conventional composites have been achieved in two ways: In one system, a hybrid polyimide‐silica coating is used to replace the existing size on the surface of glass fibers for use in epoxy matrix composites, and in the other a polyimide silica hybrid is used as the matrix of carbon‐fiber composites. In the case of coatings, the introduction of co‐continuous silica domains in a standard epoxy resin system has beneficial effects not only in terms of mechanical properties but also by making it possible to use molybdate species within the siloxane domains, which enhances the corrosion resistance through the passivation of the iron oxide formed at the interface.

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Hybridization of Nafion membranes by the infusion of functionalized siloxane precursors

Cited by 47 publications

References 33 publications

Transport Properties of Zeolite Na‐X–Nafion Membranes: Effect of Zeolite Loadings and Particle Size

Transport Properties of Zeolite Na‐X–Nafion Membranes: Effect of Zeolite Loadings and Particle Size

Polymeric organic–inorganic proton-exchange membranes for fuel cells produced by the sol–gel method

Nanostructured Polymer Composites by Sol–Gel Method

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