Nanoporous Transparent MOF Glasses with Accessible Internal Surface

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Glassy materials are versatile but lack inherent nanoscale porosity.
• Metal-organic frameworks (MOFs) offer tunable porosity but are typically crystalline.
• Developing porous glassy materials, particularly MOF-based glasses, remains an unmet challenge.

Purpose of the Study:

• To develop a generalizable chemical strategy for creating transparent, porous MOF glasses.
• To combine the design flexibility of MOFs with the properties of glassy materials.
• To achieve permanent porosity accessible to gases in MOF-based glasses.

Main Methods:

• Assembly of MOF glasses from viscous solutions of metal nodes and organic linkers.
• Evaporation of a plasticizer-modulator solvent to form the glassy structure.
• Characterization of porosity using N2 adsorption isotherms and analysis of the glass transition.

Main Results:

• Successful synthesis of transparent MOF glasses with 300 m²/g internal surface area.
• Achieved pore-pore separation of 2 nm and volumetric porosity of 0.33 cm³/cm³.
• Evidence of a 3D covalent network contributing to porosity, indicated by the disappearance of the glass transition signature.

Conclusions:

• A novel, generalizable method for producing porous MOF glasses has been established.
• The resulting MOF glasses exhibit significant porosity comparable to highly porous crystalline MOFs.
• This work bridges the gap between MOF porosity and glassy material versatility, opening new avenues for material design.