Surface Diffusion in Microstructured, Ion-Exchange Matrixes: Nafion/Neutron Track-Etched Polycarbonate Membrane Composites

Fang, Yun; Leddy, Johna

doi:10.1021/j100016a049

Cited by 34 publications

(44 citation statements)

References 18 publications

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“…On the other hand, in 10:9 v/v IPA/water mixture, a better solvent for the perfluorinated backbone, C* increases to ~4.5 g l −1 (Zhang et al 2008). As previous attempts to fill PCTE or AAO pores with Nafion (Leddy and Vanderborgh 1987, Fang and Leddy 1995, Raghav 2005, Bocchetta et al 2007) were carried out with solutions containing ≥30 g l −1 Nafion in solvents containing ≥50% water and <15% IPA, Nafion molecules must have aggregated to form large particles (>500 nm) (Jiang et al 2001, Zhang et al 2008) and were unlikely to enter 100-200-nm pores. This is also consistent with the aggregation problems during the pore-filling of PTFE membranes described in the previous section.…”

Section: Anisotropic Pore-filling Membranesmentioning

confidence: 69%

“…However, the examples of PEM preparation with AAO and PCTE membranes are even scarcer than with the isotropic supports reviewed earlier. Probably, the first publications by Leddy and Vanderborgh (1987) and Fang and Leddy (1995) presented PCTE membranes filled with Nafion from an in-house-made ~3 wt.% water-ethanol solution (50:50) by soaking and drying. A 20-fold increase in cation flux with pore diameter decreasing from 600 to 30 nm was reported, and increasing ordering of Nafion within the pores was suggested as an explanation for the phenomenon.…”

Section: Anisotropic Pore-filling Membranesmentioning

confidence: 99%

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Understanding methods of preparation and characterization of pore-filling polymer composites for proton exchange membranes: a beginner’s guide

Gloukhovski

Freger

Tsur

2017

Reviews in Chemical Engineering

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Abstract Composite membranes based on porous support membranes filled with a proton-conducting polymer appear to be a promising approach to develop novel proton exchange membranes (PEMs). It allows optimization of the properties of the filler and the matrix separately, e.g. for maximal conductivity of the former and maximal physical strength of the latter. In addition, the confinement itself can alter the properties of the filling ionomer, e.g. toward higher conductivity and selectivity due to alignment and restricted swelling. This article reviews the literature on PEMs prepared by filling of submicron and nanometric size pores with Nafion and other proton-conductive polymers. PEMs based on alternating perfluorinated and non-perfluorinated polymer systems and incorporation of fillers are briefly discussed too, as they share some structure/transport relationships with the pore-filling PEMs. We also review here the background knowledge on structural and transport properties of Nafion and proton-conducting polymers in general, as well as experimental methods concerned with preparation and characterization of pore-filling membranes. Such information will be useful for preparing next-generation composite membranes, which will allow maximal utilization of beneficial characteristics of polymeric proton conductors and understanding the complicated structure/transport relationships in the pore-filling composite PEMs.

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Section: Anisotropic Pore-filling Membranesmentioning

confidence: 69%

Section: Anisotropic Pore-filling Membranesmentioning

confidence: 99%

Understanding methods of preparation and characterization of pore-filling polymer composites for proton exchange membranes: a beginner’s guide

Gloukhovski

Freger

Tsur

2017

Reviews in Chemical Engineering

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“…Nyquist plots of empty alumina membranes and a plain film of the PEO electrolyte were Two semicircles seen for each composite polymer electrolyte membrane indicate that there are two paths for ionic conduction. The first one at higher relative resistance can be assigned to ionic conduction which occurs throughout the bulk of the polymer electrolyte, while the second one at low relative resistances can be assigned to a mechanism of ionic conduction along the interfaces bet- (1) Z' "SsE 9 R p ween the pores and the polymer surfaces [20,22]. While calculating the specific conductivity of "interfacial" conduction may be impossible to achieve because the geometry of any interfacial conduction region would be difficult to determined, there is no doubt that this conduction is much larger than that of the bulk conduction.…”

Section: Resultsmentioning

confidence: 99%

Impedance spectroscopy of PEO-lithium triflate confined in nanopores of alumina membranes

Castriota

Teeters

2005

Ionics

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Abstract. Polymeric electrolytes are very useful for their technological applications in different electrochemical devices such as batteries, electrochromic devices, smart windows, etc. One of the most studied solid electrolyte system is PEO (poly-ethylene oxide) complexed with various lithium salts. A limitation of this polymer electrolyte is low ionic conductivity. However, nanoscale manipulation of the solid polymer electrolyte has the potential to address this issue. This work discusses how it is possible to increase the PEO conductivity when this polymer is contained in nanostructures, specifically nanopores. The nanostructures used are alumina filtration membranes (thickness = 6 ~tm, diameter = 13 mm) with three different pore sizes 0.02 p~m, 0.1 ~tm and 0.2 p~m. Electrochemical characterization has been performed with an HP4194A Impedance/Gain phase analyser and Solartron 1260 Impedance/Gain phase analyser. The former instrument tests these films at a high frequency (from 100 Hz to 40 MHz) while the later at low frequency (from 1 Hz to 1 MHz). From these experiments, it has been determined that two regions of ion conduction exit. One is conduction through the bulk polymer electrolyte in the pores while the other is an interfacial conduction at the interface between the pore walls and the PEO electrolyte. The conductivity of the PEO is increased when confined in these nanostructures.

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“…If permeabilities are determined as a function of the composition and dimensions of the microstructural components, additional information about mass transport associated with the microstructures can be extracted. 43,44 When δ 0 is comparable to the scale of the microstructural characteristic lengths, these analyses will likely fail. Under these conditions, scanning electrochemical microscopy (SECM), first introduced by Bard and coworkers, 45 may be appropriate as SECM exploits interrogation of the boundary layers established about micro-to nanostructures.…”

Section: Models For Heterogeneous Films and Compositesmentioning

confidence: 99%

Film Permeation by Rotating Disk Voltammetry at Electrodes Modified with Electrochemically Inert Layers and Heterogeneous Composites

Knoche

Hettige

Zook-Gerdau

et al. 2016

J. Electrochem. Soc.

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Steady state rotating disk voltammetry provides excellent measurement of permeability for films and layers on electrodes because the hydrodynamic control of rotating disks establishes well defined boundary layers normal to the electrode. For a redox probe present in solution and pre-equilibrated in the layer, voltammetry measures electrolysis current for the probe as the probe transports from solution, through the film, and to the electrode where the probe is electrolyzed. Diagnostic equations relate the steady state, mass transport limited current iss to the rotation rate ω. The incompressible layer is electroinactive about the probe formal potential. Diagnostics are available for a single layer, uniform film (Gough and Leypoldt). Uniform films are homogeneous with no structural features. Here diagnostics are provided for bilayer and multilayer uniform films, where multilayers include discretely and continuously graded films. Consideration of serial mass transport resistances normal to the electrode allows diagnostics for uniform films. Heterogeneous, micro- and nano-structured layers are structured in the plane of the electrode. Consideration of parallel mass transport resistances as part of the layer mass transport resistance yields diagnostics for heterogeneous films. Diagnostics are vetted with literature data. Theoretical and practical advantages and limitations are noted.

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Surface Diffusion in Microstructured, Ion-Exchange Matrixes: Nafion/Neutron Track-Etched Polycarbonate Membrane Composites

Cited by 34 publications

References 18 publications

Understanding methods of preparation and characterization of pore-filling polymer composites for proton exchange membranes: a beginner’s guide

Understanding methods of preparation and characterization of pore-filling polymer composites for proton exchange membranes: a beginner’s guide

Impedance spectroscopy of PEO-lithium triflate confined in nanopores of alumina membranes

Film Permeation by Rotating Disk Voltammetry at Electrodes Modified with Electrochemically Inert Layers and Heterogeneous Composites

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