Modeling the Nanophase Structural Dynamics of Phenylated Sulfonated Poly Ether Ether Ketone Ketone (Ph-SPEEKK) Membranes as a Function of Hydration

Journal Article · Thu Mar 03 04:00:00 EST 2011 · Journal of Physical Chemistry B, 115(8):1817-1824

DOI:https://doi.org/10.1021/jp110331m· OSTI ID:1009725

Lins, Roberto D; Devanathan, Ramaswami; Dupuis, Michel

Solvated phenylated sulfonated poly ether ether ketone ketone (Ph-SPEEKK) membranes in the presence of hydronium ions were modeled by classical molecular dynamics simulations. The characterization of the nanophase structure and dynamics of such membranes was carried out as a function of the water content lambda, where lambda is the number of water molecules per sulfonate group, for lambda values of 3.5, 6, 11, 25, and 40. Analysis of pair correlation functions supports the experimental observation of membrane swelling upon hydration as well the increase in water and hydronium ion diffusion with increasing lambda. While the average number of hydrogen bonds between hydronium ions and sulfonate groups is dramatically affected by the hydration level, the average lifetime of the hydrogen bonds remains essentially constant. The membrane is found to be relatively rigid and its overall flexibility shows little dependence on water content. Compared to Nafion, water and ion diffusion coefficients are considerably smaller at lower hydration levels and room temperature. However, at higher lambda values of 25 and 40 these coefficients are comparable to those in Nafion at a lambda value of 16. This study also shows that water diffusion in Ph-SPEEKK membranes at low hydration levels can be significantly improved by raising the temperature with important implications for proton conductivity.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1009725
• Report Number(s): PNNL-SA-76059; 24811; 40083; KC0302020
• Journal Information: Journal of Physical Chemistry B, 115(8):1817-1824, Journal Name: Journal of Physical Chemistry B, 115(8):1817-1824 Journal Issue: 8 Vol. 115; ISSN 1520-6106
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
CORRELATION FUNCTIONS
DIFFUSION
ETHERS
Environmental Molecular Sciences Laboratory
FLEXIBILITY
HYDRATION
HYDROGEN
KETONES
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MEMBRANES
OXONIUM IONS
PROTONS
SIMULATION
SULFONATES
SWELLING
WATER
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molecular dynamics simulation
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solvation