scholarly journals Impact of Nano- and Mesoscales on Macroscopic Cation Conductivity in Perfluorinated-Sulfonic-Acid Membranes

2017 ◽  
Vol 121 (51) ◽  
pp. 28262-28274 ◽  
Author(s):  
Andrew R. Crothers ◽  
Clayton J. Radke ◽  
Adam Z. Weber
Keyword(s):  
Sulfonic Acid ◽  
Cation Conductivity ◽  
Perfluorinated Sulfonic Acid

Dynamic Emergence of Nanostructure and Transport Properties in Perfluorinated Sulfonic Acid Ionomers

2020 ◽  
Author(s):  
Adlai Katzenberg ◽  
Debdyuti Mukherjee ◽  
Peter J. Dudenas ◽  
Yoshiyuki Okamoto ◽  
Ahmet Kusoglu ◽  
...  
Keyword(s):  
Rate Constant ◽  
Sulfonic Acid ◽  
Mass Fraction ◽  
Gas Permeability ◽  
Transport Processes ◽  
Segmental Mobility ◽  
The Matrix ◽  
Swelling Rate ◽  
Ion Conducting ◽  
Perfluorinated Sulfonic Acid

<p>Limitations in fuel cell electrode performance have motivated the development of ion-conducting binders (ionomers) with high gas permeability. Such ionomers have been achieved by copolymerization of perfluorinated sulfonic acid (PFSA) monomers with bulky and asymmetric monomers, leading to a glassy ionomer matrix with chemical and mechanical properties that differ substantially from common PFSA ionomers (e.g., Nafion™). In this study, we use perfluorodioxolane-based ionomers to provide fundamental insights into the role of the matrix chemical structure on the dynamics of structural and transport processes in ion-conducting polymers. Through <i>in-situ</i> water uptake measurements, we demonstrate that ionomer water sorption kinetics depend strongly on the properties and mass fraction of the matrix. As the PFSA mass fraction was increased from 0.26 to 0.57, the Fickian swelling rate constant decreased from 0.8 s<sup>-1</sup> to 0.2 s<sup>-1</sup>, while the relaxation rate constant increased from 3.1×10<sup>-3</sup> s<sup>-1</sup> to 4.0×10<sup>-3</sup>. The true swelling rate, in nm s<sup>-1</sup>, was determined by the chemical nature of the matrix; all dioxolane-containing materials exhibited swelling rates ~1.5 - 2 nm s<sup>-1</sup> compared to ~3 nm s<sup>-1</sup> for Nafion. Likewise, Nafion underwent relaxation at twice the rate of the fastest-relaxing dioxolane ionomer. Reduced swelling and relaxation kinetics are due to limited matrix segmental mobility of the dioxolane-containing ionomers. We demonstrate that changes in conductivity are strongly tied to the polymer relaxation, revealing the decoupled roles of initial swelling and relaxation on hydration, nanostructure, and ion transport in perfluorinated ionomers. </p>

Spectroscopic Studies of Heteropoly Acid-doped 3M Perfluorinated Sulfonic Acid Polymer Membranes

2019 ◽  
Vol 1 (6) ◽  
pp. 255-262 ◽  
Author(s):  
Andrew M. Herring ◽  
Fanqin Meng ◽  
Matthew Frey ◽  
Steve Hamrock ◽  
John Turner ◽  
...  
Keyword(s):  
Sulfonic Acid ◽  
Heteropoly Acid ◽  
Polymer Membranes ◽  
Spectroscopic Studies ◽  
Perfluorinated Sulfonic Acid

Thermo-Optical Properties of Perfluorinated Sulfonic Acid Membranes: An Investigation of Hydration Based on Absorption Spectra

2017 ◽  
Vol 71 (11) ◽  
pp. 2504-2511 ◽  
Author(s):  
Daniele T. Dias ◽  
Guy Lopes ◽  
Tales Ferreira ◽  
Ivanir L. Oliveira ◽  
Caroline D. Rosa
Keyword(s):  
Sulfonic Acid ◽  
Room Temperature ◽  
Water Retention ◽  
Structural Changes ◽  
Optical Characterization ◽  
Scanning Calorimetry ◽  
Experimental Procedure ◽  
Nafion Membranes ◽  
Perfluorinated Sulfonic Acid

The Nafion membranes are widely used in electrochemical applications such as fuel cells, chlor-alkali cells, and actuators–sensors. In this work, the thermal-optical characterization of Nafion in acid form was performed by photoacoustic spectroscopy, thermogravimetry, and differential scanning calorimetry. In the experimental procedure three distinct hydration levels were considered: (1) pristine membrane (λ ≅ H2O/–SO3H ≅ 5.6); (2) swelling process (λ ≅ 17.4); and (3) drying at controlled room temperature after swelling process (λ ≅ 6.5). The discovered behaviors showed significant irreversible structural changes induced by water retention in the membrane. These structural changes depend on the water population present in the clusters and also affect the directional thermal diffusivity of the membrane irreversibly.

scholarly journals Evaluation of fluorine and sulfonic acid co-functionalized graphene oxide membranes under hydrogen proton exchange membrane fuel cell conditions

2019 ◽  
Vol 3 (7) ◽  
pp. 1790-1798 ◽  
Author(s):  
Robin Sandström ◽  
Alagappan Annamalai ◽  
Nicolas Boulanger ◽  
Joakim Ekspong ◽  
Alexandr Talyzin ◽  
...  
Keyword(s):  
Sulfonic Acid ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Two Dimensional ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Perfluorinated Sulfonic Acid ◽  
Exchange Membrane ◽  
Oxide Membranes ◽  
Graphene Oxide Membranes

Two-dimensional perfluorinated sulfonic acid represent an intriguing new proton exchange membrane concept.

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