Aquivion® PFSA (perfluorosulfonic acid) ionomer membranes, dispersions and other perfluorinated product forms are key enablers for electrical storage and conversion devices, such as fuel cells, electrolyzers and flow batteries used in conjunction with zero-emission electricity sources.

Solvay’s Aquivion® portfolio offers the industry's broadest range of PFSA compositions and product forms, which includes ionomer membranes, dispersions, powders and melt-processable pellets. These innovative materials are based on the Short Side Chain (SSC) copolymer of Tetrafluoroethylene (TFE) and Sulfonyl Fluoride Vinyl Ether (SFVE) F2C=CF-O-CF2CF2-SO2F.

 

Aquivion® Product Forms

  • Membranes (PFSA)

  • Dispersions (PFSA, PFSO3Li)

  • Powders (PFSA, PFSO3Li)

  • Pellets (PFSF)


PFSO3Li represents the lithium salt form (-SO3Li) of PFSA. 

PFSF (perfluorosulfonic fluoride) pellets, due to a sulfonyl fluoride group (-SO2F), are the only product forms that can be melt extruded and then successively converted into the ionic (-SO3H) PFSA form. 
 

Key Advantages

  • Very high concentration of functional groups for strong proton (or Na+, K+, Li+) conductivity

  • High softening point for high-temperature operation well above 80°C

  • Strong water retention for better low-humidity fuel cell operation

Aquivion® PFSA’s shorter side chain makes it possible to achieve either better mechanical properties at the same IEC (ion-exchange capacity) or a higher IEC at the same mechanical properties than long side chain polymers (LSC).

Aquivion_Short-side-chain_550px-247697

 

Comparison of short side chain (SSC) and long side chain (LSC) ionomers 
Measurements made using Perkin-Elmer DSC7 Calorimeter

Aquivion-Heat-of-fusion-vs-EW_670px-247694

Product Data

PFSA Membranes

Aquivion® PFSA melt-extruded ionomer membranes are available in the acid form and feature a lower Equivalent Weight (EW) than most other commercial proton exchange membranes. Nominal thicknesses range from 50 – 150 microns.

The material’s distinctive Short Side Chain ionomer imparts higher crystallinity, improved mechanical properties and better proton conductivity.

Typical Applications

  • PEM fuel cells
  • PEM water electrolyzers
  • Electrochemical hydrogen compressors
  • Separators for redox flow batteries
  • Pervaporation or gas humidification systems
Aquivion® Grade EW (g/eq) Thickness (Microns)
E87-05S* 870 50
E87-12S* 870 120
E98-05 980 50
E98-05S* 980 50
E98-09S* 980 90
E98-15S* 980 150

*S-suffix indicates chemical polymer stabilization

PFSA and Lithium Salt Dispersions

Aquivion® PFSA dispersions contain the acid form (R-SO3H) and are available in various solvent systems, Equivalent Weights (EWs) and concentrations. One grade is in Lithium salt form (R-SO3Li).

Solvay’s sophisticated dispersion technology uses innocuous solvents and provides products which remain Newtonian at aqueous state (see graphs below) or when mildly formulated with n-propanol.

Typical Applications

  • Inks for PEM fuel cell electrodes
  • Manufacture or repair of ion exchange membranes
  • Synthesis of super-acid catalysts
  • Surface treatment of PTFE membranes to improve wetting behavior
  • Components for electrochemical devices (OLED, Li-batteries, etc.)
Aquivion-viscosity-vs-shear-rate_670px-247695

Shear-thinning behavior for various Aquivion® PFSA dispersions

Aquivion® Grade EW (g/eq) Polymer (wt%) Solvent System
D72-25BS* 720 25 >99% water, free of ethers
D79-25BS* 790 25 >99% water, free of ethers
D79-25BSLi 790 25 >99% water, free of ethers
D83-06A 830 6 20% water, 40% 1-propanol, 
40% 2-propanol
D83-24B 830 24 >99% water, free of ethers
D98-25BS* 980 25 >99% water, free of ethers

*S-suffix indicates chemical polymer stabilization

 

PFSF Pellets

Aquivon® PFSF (perfluorinated sulfonyl fluoride) pellets are the first commercially available SSC sulfonyl fluoride precursor resins. They are the only form that can be melt extruded, due to the sulfonyl fluoride group (-SO2F), and then successively converted into their ionic form (-SO3X, X=H/Na/K/Li).

These innovative materials enrich the still scarce industry offerings of melt processable precursor resins. Molded shapes can actively serve the chemical industry as durable catalytic or ion-exchange materials after their chemical activation.

Aquivion® Grade EW (g/eq)
P87S-SO2F* 870
P98-SO2F 980

*S-suffix indicates chemical polymer stabilization

PFSA and Lithium Salt Powders

Aquivion® PFSA ready-to-use powders can serve directly as heterogeneous acid catalysts or exchange resins. They often offer greater chemical resistance than conventional exchange resins, making them better suited for exposure to aggressive environments. A lithium salt powder is also available.

Low Equivalent Weight (EW) grades deliver significantly higher electrochemical functionality per unit mass than competitive PSFA products. The higher crystallinity of high-end EW grades (98 series) can help to improve the mechanical robustness and durability of the finished PFSA parts.

Typical Applications

  • Heterogeneous acid catalysts
  • Ion-Exchange resins
  • Components for electrochemical devices
  • Ion exchange membranes
Aquivion® Grade Functional Group EW (g/eq)
PW79S* R-SO3H 790
PW79S-Li* R-SO3Li 790
PW87S* R-SO3H 870
PW98 R-SO3H 980

*S-suffix indicates chemical polymer stabilization

Technical Data Sheets
Aquivion® Grade Form Description
D72-25BS* Dispersion, Ionomer Chemically-stabilized. Nominal equivalent weight of 720 g/eq. Polymer concentration is 25%. Solvent system is >99% water and is free of ethers.
D79-25BS* Dispersion, Ionomer Chemically-stabilized. Nominal equivalent weight of 790 g/eq. Polymer concentration is 25%. Solvent system is >99% water and is free of ethers.
D79-25BSLi* Dispersion, Lithium Salt Chemically-stabilized. Nominal equivalent weight of 790 g/eq. Polymer concentration is 25%. Solvent system is >99% water and is free of ethers.
D83-06A Dispersion, Ionomer Nominal equivalent weight of 830 g/eq. Polymer concentration is 6%. Solvent system is 20% water, 40% 1-propanol and 40% 2-propanol.
D83-24B Dispersion, Ionomer Nominal equivalent weight of 830 g/eq. Polymer concentration is 24%. Solvent system is >99% water and is free of ethers.
D98-25BS Dispersion, Lithium Salt Chemically-stabilized. Nominal equivalent weight of 980 g/eq. Polymer concentration is 25%. Solvent system is >99% water and is free of ethers.
E87-05S* Dispersion, Lithium Salt Chemically-stabilized. Nominal equivalent weight of 870 g/eq. Nominal thickness is 50 microns.
E87-12S* Membrane, Ionomer Chemically-stabilized. Nominal equivalent weight of 870 g/eq. Nominal thickness is 120 microns.
E98-05 Membrane, Ionomer Nominal equivalent weight of 980 g/eq. Nominal thickness is 50 microns.
E98-05S* Membrane, Ionomer Chemically-stabilized. Nominal equivalent weight of 980 g/eq. Nominal thickness is 50 microns.
E98-09S* Membrane, Ionomer Chemically-stabilized. Nominal equivalent weight of 980 g/eq. Nominal thickness is 90 microns.
E98-15S* Membrane, Ionomer Chemically-stabilized. Nominal equivalent weight of 980 g/eq. Nominal thickness is 150 microns.
P87S-SO2F* Pellets, Perfluorinated Sulfonyl fluoride form. Nominal equivalent weight of 870 g/eq.
P98-SO2F Pellets, Perfluorinated Sulfonyl fluoride form. Nominal equivalent weight of 980 g/eq
PW79S* Powder, Coarse Acid Chemically-stabilized. Nominal equivalent weight of 790 g/eq.
PW79S-Li* Powder, Coarse Lithium Salt Chemically-stabilized. Nominal equivalent weight of 790 g/eq.
PW87S* Powder, Coarse Acid Chemically-stabilized. Nominal equivalent weight of 870 g/eq.
PW98 Powder, Coarse Acid Nominal equivalent weight of 980 g/eq.

*S-suffix indicates chemical polymer stabilization