Investigating intermolecular interactions among CO₂, water and PEEK-ionene membrane using cryo ToF-SIMS and isotopic...

Area of Science:

• Materials Science
• Chemical Engineering
• Analytical Chemistry

Background:

• Polymer-based membranes are crucial for efficient carbon dioxide (CO2) capture.
• PEEK-ionene membranes show promise for CO2 capture due to selectivity and durability.
• Understanding CO2 diffusion mechanisms and water vapor influence is vital for optimizing these membranes.

Purpose of the Study:

• To investigate CO2 and water interactions within PEEK-ionene membranes using cryo ToF-SIMS.
• To elucidate the role of water vapor in CO2 diffusion and membrane performance.
• To assess the potential of cryo ToF-SIMS for analyzing gas-membrane-water systems.

Main Methods:

• Application of cryogenic time-of-flight secondary ion mass spectrometry (cryo ToF-SIMS).
• Loading PEEK-ionene membranes with 13CO2 and D2O.
• 3D visualization of CO2 and water distribution within the membrane structure.

Main Results:

• Cryo ToF-SIMS indicated weak CO2-PEEK-ionene interactions, with CO2 vaporizing at low temperatures.
• D2O exhibited homogeneous distribution, suggesting strong hydrogen bonding with the membrane (18-20 kJ/mol).
• CO2 was not detected in D2O-loaded membranes, implying minimal water vapor interference with CO2 diffusion.

Conclusions:

• Cryo ToF-SIMS is effective for studying gas-water-membrane interactions in CO2 capture materials.
• Weak CO2-membrane interactions limit capture efficiency in PEEK-ionene.
• Insights gained can guide membrane functionalization for enhanced CO2 capture.