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Updated: Sep 23, 2025
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Assembly and Characterization of Biomolecular Memristors Consisting of Ion Channel-doped Lipid Membranes
Published on: March 9, 2019
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Characterization and Modeling of Free Volume and Ionic Conduction in Multiblock Copolymer Proton Exchange Membranes
Mahmoud Mohammed Gomaa1, Arturo Sánchez-Ramos2, Nieves Ureña3
1Physics Department, Faculty of Science, Minia University, Minia P.O. Box 61519, Egypt.
Polymers
|May 14, 2022
Summary
Free volume in proton exchange membranes (PEMs) impacts transport. Synthesized sulfonated polysulfone copolymers show lower ionic conductivity than Nafion® due to reduced free volume and increased tortuosity.
Area of Science:
- Materials Science
- Polymer Chemistry
- Electrochemistry
Background:
- Free volume is critical for transport properties in proton exchange membranes (PEMs).
- Understanding free volume's role is essential for developing efficient PEMs for fuel cells.
- Polysulfone/polyphenylsulfone multiblock copolymers (SPES) are investigated as potential PEM materials.
Purpose of the Study:
- To characterize the pore size distribution and ionic conductivity of synthesized SPES.
- To investigate the influence of free volume on water uptake and proton conduction in SPES.
- To compare the transport properties of SPES with Nafion®.
Main Methods:
- Positron annihilation lifetime spectroscopy (PALS) for free volume characterization.
- Electrochemical impedance spectroscopy (EIS) for ionic conductivity measurement.
- Bundle-of-tubes model for cluster-network scale analysis.
Main Results:
- SPES exhibits stable free pore size across temperatures, indicating good thermo-mechanical properties.
- Synthesized SPES has significantly lower free volume compared to Nafion®.
- Lower free volume in SPES leads to reduced ionic conductivity due to restricted proton transfer pathways and increased network tortuosity.
Conclusions:
- The free volume in SPES is a limiting factor for its ionic conductivity.
- SPES materials demonstrate potential but require optimization to enhance proton transport for fuel cell applications.
- The study highlights the trade-off between thermo-mechanical stability and ionic conductivity influenced by free volume in PEMs.
Keywords:
PALSSPESelectrochemical impedance spectroscopyfree volumeionic conductivitymodelingproton exchange membraneMore Related Videos
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