Interparticle Forces of a Native and Encapsulated Metal-Organic Framework and Their Effects on Colloidal Dispersion

Area of Science:

• Materials Science
• Colloid Science
• Nanotechnology

Background:

• Colloidal properties of metal-organic frameworks (MOFs) are crucial for their use in device fabrication.
• Quantifying interaction forces in MOF suspensions is essential for controlling their stability and application.

Purpose of the Study:

• To quantify van der Waals attractive, electric double layer repulsive, and steric repulsive forces for native and encapsulated MOFs.
• To predict MOF suspension properties using the extended Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory.
• To evaluate the dispersion state of MOFs in various solvents and correlate with theoretical predictions.

Main Methods:

• Environmental ellipsometric porosimetry (EEP) and spectroscopic ellipsometry (SE) for van der Waals forces.
• Colloid and material characterization for repulsive forces.
• Extended DLVO theory for predicting suspension properties.
• Dispersion quantification in nine solvents.

Main Results:

• First-time quantification of attractive and repulsive forces in MOF colloids.
• Successful prediction of suspension properties using extended DLVO theory.
• MOFs with surface-selective encapsulation demonstrated superior suspension in hydrophobic solvents.

Conclusions:

• The study provides a quantitative understanding of forces governing MOF colloidal stability.
• Surface modification is a viable strategy to enhance MOF dispersibility in specific solvents.
• Findings will accelerate the development of stable MOF colloidal suspensions for advanced applications.