Chemical and homogeneity changes of a Nafion membrane surface associated to its doping with the cation of the room‐temperature ionic liquid AliquatCl

Yuso, M. Valle Martínez de; Calderón, Andrea; Romero, V.; Cuberes, M. Teresa; Benavente, J.

doi:10.1002/sia.5984

Cited by 3 publications

(1 citation statement)

References 20 publications

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“…A close examination of XPS literature over the last few decades reveals discrepancies in assignment of these O1s peak signals to the two possible atomic configurations within the Nafion structure. Upon examination of 25 prior publications, 52% assign the peak at E b ∼533.0 eV to oxygen atoms in the -SO 3 − configuration and the peak at E b ∼535.7 eV to oxygen in the ether configuration (n = 13 papers); 15,23,[30][31][32][33][34][35][36][37][38][39][40] 40% assign the peaks in the opposite arrangement, with -SO 3 − oxygen atoms identified as signal at 535.7 eV and ether atoms at 533.0 eV (n = 10). [41][42][43][44][45][46][47][48][49][50] Another two papers (8% of the literature) identify these binding energies as O1s signals but are careful not to differentiate or assign the peaks to specific configurations.…”

Section: Resultsmentioning

confidence: 99%

Mapping Microscale Chemical Heterogeneity in Nafion Membranes with X-ray Photoelectron Spectroscopy

Friedman

Shi

Losovyj

et al. 2018

J. Electrochem. Soc.

112

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Nafion has found utility in a wide variety of applications, particularly as the most commonly used electrolyte membrane in fuel cell technology. Despite decades of characterization by X-ray Photoelectron Spectroscopy (XPS), a dispute exists within literature over the proper assignment of oxygen binding energies from the ether and sulfonate functional groups present in Nafion. Here, we have employed highly oriented pyrolytic graphite (HOPG) as an internal standard to calibrate all XPS spectra and are able to correlate binding energies from C1s, O1s, F1s and S2p to the Nafion structure. Further, microscale heterogeneities inherent to this formulation of Nafion membranes are revealed through two-dimensional XPS mapping of membrane cross-sections as well as surface ablation via Ar + ion sputtering. Results clearly show Nafion membranes are comprised of two chemically distinct layers: a surface layer several microns thick that is comprised of sulfonate groups and an inner layer that shields the more non-polar perfluoroether moieties.

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Section: Resultsmentioning

confidence: 99%

Mapping Microscale Chemical Heterogeneity in Nafion Membranes with X-ray Photoelectron Spectroscopy

Friedman

Shi

Losovyj

et al. 2018

J. Electrochem. Soc.

112

View full text Add to dashboard Cite

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Processing, Characterization, and Impact of Nafion Thin Film on Photonic Nanowaveguides for Humidity Sensing

Tian

Meng

et al. 2021

Advanced Photonics Research

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Herein, the impact and spin‐coating process of Nafion thin films on photonic nanowaveguide structures fabricated via a complementary metal–oxide–semiconductor compatible process for the first time is investigated. Particularly, the effect of Nafion thin films (≈23–776 nm) on microring resonators (MRRs) with compact waveguide sizes (480 nm by 220 nm and 380 nm by 220 nm) is focused on, where the microring provides enhanced interactions between the Nafion and light, which is related to Nafion thin‐film properties such as the refractive index, water uptake, and swelling. The results demonstrate small, compact, and cost‐effective MRR devices to characterize Nafion thin film and high‐resolution on‐chip humidity sensing for real‐time and continuous measurements.

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New Insights on the Effects of Water on Polymer Inclusion Membranes Containing Aliquat 336 Derivatives as Carriers

et al. 2022

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Surface characterization of polymer inclusion membranes (PIMs) using the polymers cellulose triacetate and polyvinyl chloride, containing different ionic liquids (ILs) as carriers, has been performed. Three different ILs have been tested: commercial trioctyl methylammonium chloride (Aliquat 336–AlqCl−) and two derivatives bearing the counter anion NO3− or SCN− (AlqNO3 and AlqSCN, respectively). Surface analysis was performed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) for both dry membranes and PIMs immersed for 4 days in ultrapure water to investigate the effect of the interaction of water with the membrane’s morphology and composition. XPS analysis of the PIMs revealed that immersion in ultrapure water causes a decrease in the atomic concentration percentage (A.C.%) of the specific IL atoms (Cl, S, and N) when compared with dry samples. Moreover, SEM images of the PIMs containing the IL AlqNO3 showed an alteration in the morphology of the membrane due to water contact at surface level, whereas no changes were observed at a bulk level. These changes in the surface composition of the water equilibrated PIMs may be associated with the solubilization of the IL in the water solution, which, therefore, may affect the reactivity of the membrane’s surface. To better understand this effect, PIMs containing both AlqCl and AlqNO3 as carriers were used for arsenic (V) transport. It was found that AlqCl was the most effective IL and that the effectivity of the PIM on As(V) removal was not affected after five cycles of the membrane’s reuse.

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Chemical and homogeneity changes of a Nafion membrane surface associated to its doping with the cation of the room‐temperature ionic liquid AliquatCl

Cited by 3 publications

References 20 publications

Mapping Microscale Chemical Heterogeneity in Nafion Membranes with X-ray Photoelectron Spectroscopy

Mapping Microscale Chemical Heterogeneity in Nafion Membranes with X-ray Photoelectron Spectroscopy

Processing, Characterization, and Impact of Nafion Thin Film on Photonic Nanowaveguides for Humidity Sensing

New Insights on the Effects of Water on Polymer Inclusion Membranes Containing Aliquat 336 Derivatives as Carriers

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