Alkali-ion-modified zeolitic imidazolate framework glasses

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Silicate glass modification is crucial for applications like optical fibers and membranes.
• Metal-organic frameworks (MOF) offer tunable properties but their glassy forms require similar modification strategies.

Purpose of the Study:

• To investigate the effect of incorporating compatible glass modifiers, specifically sodium benzimidazolate (Na(bim)), into MOF glasses.
• To understand how these modifications alter the structural, thermal, and physical properties of MOF glasses.

Main Methods:

• Melt-quenching of ZIF-62 MOF glass former with varying Na(bim) content.
• Characterization using thermal analysis (T_g, fragility), density measurements, spectroscopy, and X-ray diffraction.
• Computational modeling using density-functional theory (DFT).

Main Results:

• Systematic decrease in glass transition temperature (T_g) and increased liquid fragility with higher Na(bim) content.
• Incorporation of Na(bim) into the MOF glass framework, leading to partial network depolymerization and increased density.
• Water treatment successfully increased glass porosity, mimicking processes used for borosilicate glasses.

Conclusions:

• Na(bim) acts as an effective modifier for MOF glasses, enabling property tuning analogous to silicate glasses.
• The study demonstrates a transferable method for designing and optimizing MOF glasses for advanced applications.
• This work opens new avenues for creating functional MOF-based materials through controlled chemical modification.