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Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells
Published on: November 12, 2020
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Persistent Subdiffusive Proton Transport in Perfluorosulfonic Acid Membranes
1Department of Chemistry, James Franck Institute, and Computation Institute, University of Chicago, Chicago, Illinois 60637, United States.
The Journal of Physical Chemistry Letters
|August 18, 2015
Summary
Proton transport in perfluorosulfonic acid (PFSA) membranes is subdiffusive, showing strong dependence on water concentration. This proton movement is caged for up to 1 nanosecond, requiring longer simulations for full characterization.
Area of Science:
- Physical Chemistry
- Materials Science
- Computational Chemistry
Background:
- Proton transport (PT) in small amphiphile solutions is subdiffusive over long timescales.
- Perfluorosulfonic acid (PFSA) membranes are crucial amphiphilic systems for various applications.
- Understanding PT in PFSA membranes is essential for optimizing their performance.
Purpose of the Study:
- To investigate proton transport dynamics in hydrated PFSA membranes.
- To determine if PT in PFSA membranes exhibits subdiffusive behavior.
- To analyze the influence of hydration levels on PT and proton caging.
Main Methods:
- Analysis of molecular dynamics simulations of hydrated PFSA membranes.
- Examination of proton transport over several hundred picoseconds.
- Application of a novel technique to study proton caging effects.
Main Results:
- Proton transport in PFSA membranes is subdiffusive across all studied hydration levels.
- Subdiffusive behavior is significantly dependent on water concentration.
- Excess protons exhibit caging effects persisting up to at least 1 nanosecond.
Conclusions:
- Proton transport in PFSA membranes is confirmed to be subdiffusive.
- Water concentration critically influences the nature of proton transport.
- Accurate long-time characterization of PT in PFSAs necessitates multi-nanosecond simulation trajectories, exceeding current ab initio molecular dynamics capabilities.
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