Mixed-Matrix Membranes Formed from Imide-Functionalized UiO-66-NH₂ for Improved Interfacial Compatibility.

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Mixed-matrix membranes (MMMs) comprising metal-organic frameworks (MOFs) in polymers offer superior separation potential over pure polymers.
• Interfacial incompatibility between MOFs and polymers leads to defects, hindering performance and real-world application.
• Developing defect-free MMMs is crucial for accurate property modeling and establishing structure-property relationships.

Purpose of the Study:

• To develop a method for creating defect-free MMMs by addressing interfacial issues.
• To improve the gas separation performance of MMMs through enhanced MOF-polymer compatibility.
• To enable reliable prediction of pure MOF properties using transport models.

Main Methods:

• Surface functionalization of UiO-66-NH2 MOF particles with a nanoscopic shell of specific oligomers.
• Fabrication of MMMs using functionalized MOFs and a polymer with identical surface chemistry.
• Gas separation performance testing and property prediction using the Maxwell model.

Main Results:

• Defect-free MMMs with uniform particle dispersion were successfully fabricated.
• Gas permeabilities and selectivities were significantly enhanced across various MOF loadings (5-40 wt %).
• At 40 wt % loading, CO2 permeability increased by 48% and CO2/CH4 selectivity by 15%.

Conclusions:

• Surface functionalization is an effective strategy to eliminate interfacial defects in MMMs.
• The developed MMMs exhibit superior gas separation performance compared to traditional MMMs.
• The method facilitates accurate prediction of intrinsic MOF properties, aiding material design.