Quantifying Metal-Organic Framework (MOF)-Polymer Adsorption Using Single-Particle Langmuir Isotherm Testing (SPLIT)

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Polymer-MOF interactions are crucial for composite materials but are hard to study.
• Existing methods often use indirect measurements and average results.

Purpose of the Study:

• To introduce a new method, SPLIT, for quantifying single MOF-polymer interactions.
• To enable direct measurement of thermodynamic properties and polymer behavior.

Main Methods:

• Single-particle Langmuir isotherm testing (SPLIT) using atomic force microscopy (AFM).
• Measuring adhesion forces between a MOF-coated AFM probe and a reference surface.
• Analyzing adhesion force variations with polymer concentration to determine binding energies.

Main Results:

• SPLIT accurately quantifies polymer adsorption onto single MOF particles.
• The method provides thermodynamic properties like MOF-polymer binding energies.
• SPLIT offers insights into polymer molecular weight effects and solvent interactions.

Conclusions:

• SPLIT is a powerful technique for characterizing MOF-polymer interactions at the single-particle level.
• This method provides direct relevance for designing advanced composite materials, including mixed-matrix membranes.
• SPLIT measurements can predict polymer concentrations that cause MOF aggregation.