Is Nafion water soluble?
No differences were found at 20 and 32°C, the two temperatures important to the present study. The solubilities in Nafion™ 117 are as follows: water, 22.0 g/g; methanol, 49.2 g/g; ethanol 45.0 g/g; propanol 48.6 g/g.
How do Nafion membranes dissolve?
1, it is observed that at 80 °C, which is a common operating temperature of PEMFCs, the membrane is dissolved by solvents containing methanol higher than 20 mol%. Even at 35 °C, which is a possible temperature of portable devices, a solvent containing methanol higher than 60 mol% dissolves the membrane.
Is Nafion soluble in ethanol?
Acid pretreatment reduced Nafion film density by ∼15%. Unheated recast films were 22-100% soluble in a sonicated ethanol/water mixture. Commercial membranes and recast films heated for as little as 10 min were insoluble under the same conditions.
Is Nafion hydrophilic or hydrophobic?
In a Nafion membrane, hydrophilic sulfonic acid head groups (–SO3H) aggregate to form ionic channels of about 3–6 nm in diameter that are distributed in a hydrophobic Teflon matrix. In different versions of Nafion, the degree of hydrophilicity of the channels is tuned by a variation of the –SO3H density in the polymer.
How do you dissolve Nafion pellets?
Nafion is sulfonated teflon (PTFE) which is practically insoluble in commonly used solvents. However, Perfluorocarbon Solvents can be used to dissolve nafion as per the attached article.
What is the difference between Nafion 115 and Nafion 117?
Though the composite membrane has a lower conductivity than Nafion membrane, however, owing to the thinner thickness of composite membrane (in thickness of 20±5 µm) than Nafion-115 (in thickness of 125 µm) and Nafion-117 (in thickness of 175 µm) membranes, the composite membrane has a shorter H+ ion transporting …
What is recast Nafion?
Recast Nafion films have lower wetted density than wetted commercial and fully annealed films. Sufficient heating (140 °C for ≥40 min) yields a recast film with the same wetted density as commercial Nafion films. Fully protonated films have higher density than as-received materials.
Is Nafion membrane porous?
In practically all applications Nafion membranes are used as dense, non-porous flat sheet membranes with smooth surfaces.
Is Nafion gas permeable?
Abstract. The gas permeability of dry Nafion films was determined at 2 atm and 35 °C for He, H2, N2, O2, CO2, CH4, C2H6, and C3H8. In addition, gas sorption isotherms were determined by gravimetric and barometric techniques as a function of pressure up to 20 atm.
What is Nafion used for?
Nafion has found use in fuel cells, electrochemical devices, chlor-alkali production, metal-ion recovery, water electrolysis, plating, surface treatment of metals, batteries, sensors, Donnan dialysis cells, drug release, gas drying or humidifaction, and superacid catalysis for the production of fine chemicals.
What does Nafion 117 mean?
Nafion membranes are commonly categorized in terms of their EW and thickness. For example, Nafion 117 indicates an extrusion-cast membrane with 1100 g/mol EW and 0.007 inches (7 thou) in thickness.
What is Nafion binder?
Nafion binder is known to increase the electrochemically active surface area in the catalyst layer and the interfacial adhesion between the membrane and the electrode, thus decreasing cell resistance [17]. These factors bring enhanced performance in the fuel cells.
How do you make Nafion solution?
Prepare a mixture containing 80-85 mL of ethyl alcohol and 20-15 mL of water. Keep on adding the above mixture solution in 5 wt% Nafion® 117 solution till the total volume of diluted Nafion® 117 solution becomes appxo. 20 times the original volume . It will be 0.25 wt% Nafion solution.
Can water pass through Nafion membrane?
Nafion very readily absorbs water, from the vapor phase or from the liquid phase. Each sulfonic acid group will absorb up to 13 molecules of water. The sulfonic acid groups form ionic channels through the bulk hydrophobic polymer, and water is very readily transported through these channels.
What kind of polymer is Nafion?
fluoropolymer-copolymer
Nafion is a brand name for a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Walther Grot of DuPont. Nafion is a brand of the Chemours company. It is the first of a class of synthetic polymers with ionic properties that are called ionomers.
What is the use of Nafion?
How do you make a 5% Nafion solution?
Bottles marked 5% Nafion® 117 solution containing 15-20% water is available in the market in various capacities. Prepare a mixture containing 80-85 mL of ethyl alcohol and 20-15 mL of water.
What is Nafion made of?
Nafion comprises a polytetrafluoroethylene (PTFE) backbone with perfluorinated-vinyl-polyether side chains containing sulphonic acid end groups. When this material is hydrated, protons (H+ ions) become highly mobile, so that its proton conductivity can range up to 0.2 S/cm depending on the level of hydration (S = 1/ω).
Is Nafion a polymer?
Nafion is a perfluorosulfonic acid polymer with a good chemical stability. Its characteristics make it a material of choice as a proton exchange membrane(3).
What is Nafion membrane used for?
Widely used in electrochemical cells, they function as cation-conducting solid electrolytes. Nafion™ membranes come in a variety of grades and embody different properties, allowing designers and engineers to match membranes to their specific application needs.