Structure and proton conduction in sulfonated poly(ether ether ketone) semi-permeable membranes: a multi-scale...

Area of Science:

• Materials Science
• Computational Chemistry
• Electrochemistry

Background:

• Polymeric membranes are crucial for proton exchange applications.
• Understanding the relationship between membrane structure and proton transport is key for designing efficient membranes.
• Electrostatic forces significantly influence membrane segregation and proton conduction.

Purpose of the Study:

• To analyze the morphology of sulfonated poly(ether ether ketone) membranes using a multi-scale computational approach.
• To investigate the impact of polymer concentration, degree of sulfonation, and confinement on proton conduction.
• To establish relationships between membrane structure and proton transport properties.

Main Methods:

• Multi-scale computational modeling incorporating Brownian dynamics for polymer chains and convection-diffusion equations for proton concentration.
• Simulation of sulfonated poly(ether ether ketone) membranes with varying parameters.
• Analysis of mesoscale morphology and proton conduction mechanisms.

Main Results:

• Reduced polymer chain mobility above overlap concentration and moderate sulfonation (around 30%) promote membrane segregation and proton domain connectivity.
• Membrane conductivity is linearly dependent on polymer concentration and quadratically dependent on the degree of sulfonation.
• Optimal membrane design involves polymer concentration above overlap and sulfonation around 50%, leading to stable proton channel density.

Conclusions:

• The study validates a computational model against experimental data, confirming its predictive power.
• Optimal polymeric membrane design for proton exchange relies on achieving specific polymer concentrations and degrees of sulfonation.
• The findings provide fundamental insights into designing advanced polymeric membranes for efficient proton transport.