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Nafion
About: Nafion is a research topic. Over the lifetime, 9110 publications have been published within this topic receiving 320865 citations.
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TL;DR: In this article, a poly(arylene ether sulfone) multiblock copolymer with naphthalene hydrophobic units was synthesized via oligomeric sulfonation.
Abstract: Poly(arylene ether sulfone) multiblock copoly. were synthesized via oligomeric sulfonation. The successful oligomeric sulfonation enabled multiblock copolymer membranes with different hydrophobic block moiety (biphenyl and naphthalene units). High local concentration of sulfonic acid groups within the hydrophilic blocks enhanced the phase separation between hydrophilic and hydrophobic moiety. Rigid, nonpolar, and planar hydrophobic moiety such as naphthalene groups were effective in increasing proton conductivity and decreasing gas permeability. The multiblock copolymers with naphthalene hydrophobic units with IEC = 2.01 mequiv/g showed comparable proton conductivity to Nafion NRE 212 membrane (0.91 mequiv/g) at >40% RH. The longer blocks were found to increase a characteristic factor (ratio of the proton conductivity to the water volume fraction) as well as phase separation. The membrane showed relatively low oxidative stability under Fenton’s test conditions due to higher water uptake and swelling. Howe...
93 citations
TL;DR: In addition to providing an elegant means of controlling the ionic cluster size, the strategic approach of using CNT both as an anchoring backbone for -SO(3)H groups to enrich proton conductivity and as a blending agent to improve the mechanical characteristics of the Nafion phase might be helpful in alleviating many critical problems associated with the use of commercial Nafions.
Abstract: The application of sulfonic acid-functionalized multiwalled (s-MWNT) carbon nanotubes to manipulate the hydrophilic domain size of Nafion membranes is explored here as an option for tuning the proton conductivity of polymer electrolyte membranes for hydrogen−oxygen fuel cells. The electrochemical impedance experiments provide preliminary evidence of increased proton conductivity, while small-angle X-ray scattering measurements line out enhanced ionic cluster domain size in these composite membranes as the central reason for higher conductivity (70 A for the optimum composite membrane vs 50 A for Nafion 115) values. Scanning electrochemical microscopy indicates synergistic interaction between the sulfonic acid functional groups present in the Nafion membrane and those on the nanotube surface. More interestingly, the nanotube-tailored Nafion membranes ameliorate the performance of fuel cells as confirmed by measurements at a single-cell level, which reveal a maximum power density of 380 mW cm−2, higher than...
92 citations
TL;DR: In this paper, the authors investigated the oxygen reduction reaction in Nafion 117 and a sulfonated poly (arylene ether sulfone) membrane under 1 atm oxygen pressure, 100% relative humidity in a temperature range of 303-343 K using a solid-state electrochemical cell.
92 citations
TL;DR: In this paper, Nafion ionomer content of the cathode layer of a PEFC made by the decal-hot pressing method was investigated for its effect on performance and structure of the membrane electrode assembly (MEA).
92 citations
TL;DR: In this article, the separation of alcohol/water mixtures by Nafion hollow fiber membranes is reported; water is the preferred permeate The permeation rates and separations were shown to be highly dependent on the type of counter-ions for the alkali cation series, flux decreases in the following sequence: H > Li > Na > K > Cs This sequence is reversed for the separation factor.
92 citations