Tailoring molecular interactions between microporous polymers in high performance mixed matrix membranes for gas...

Area of Science:

• Materials Science
• Chemical Engineering
• Polymer Chemistry

Background:

• Membrane technology is vital for energy-efficient chemical separations.
• Polymers of intrinsic microporosity (PIMs) offer high gas transport but suffer from plasticization and physical aging, limiting industrial application.
• Existing PIMs face challenges with polymer chain mobility, impacting long-term stability and separation efficiency.

Purpose of the Study:

• To develop a novel membrane material that overcomes plasticization and physical aging in PIMs.
• To enhance gas transport selectivity and overall membrane performance through molecular interactions.
• To investigate the role of porous aromatic framework (PAF) additives in modifying PIM properties.

Main Methods:

• Fabrication of composite membranes using a polymer of intrinsic microporosity (PIM) matrix and a porous aromatic framework (PAF-1) additive.
• Utilized spectroscopic characterization techniques to analyze molecular interactions between PIM and PAF-1.
• Conducted control experiments with modified PIMs (PIM-EA(Me2)-TB and PIM-EA(H2)-TB) to confirm interaction mechanisms.

Main Results:

• Identified specific molecular interactions: adsorption of methyl groups from the PIM matrix into PAF-1 nanopores.
• Demonstrated a 50% reduction in physical aging of the membrane material.
• Observed suppression of polymer chain mobility at high pressures and increased H2 selectivity over CH4 and N2.

Conclusions:

• The integration of PAF-1 into PIM membranes effectively mitigates plasticization and physical aging.
• Molecular interactions between PIM methyl groups and PAF-1 pores are key to improved membrane stability and performance.
• This composite membrane design offers a promising pathway for advanced industrial gas separations.