Can a Covalent-Organic Framework Sustain Structural Integrity during Activation? Microscopic Insight from Molecular
Saad Aldin Mohamed1, Jianwen Jiang1
1Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576, Singapore.
The Journal of Physical Chemistry Letters
|July 27, 2026
Summary
Covalent-organic frameworks (COFs) can collapse during activation. This study shows solvent surface tension dictates COF structural integrity, identifying hexane and perfluorohexane as ideal solvents for stable COF activation.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Covalent-organic frameworks (COFs) are advanced nanoporous materials with broad application potential.
- COF activation is often challenging due to potential structural collapse upon solvent removal.
- Understanding solvent effects is crucial for preserving COF structural integrity.
Purpose of the Study:
- To investigate the structural stability of an imine-based COF during activation using six different solvents.
- To elucidate the relationship between solvent properties and COF structural integrity.
- To provide guidance for selecting appropriate solvents for COF activation.
Main Methods:
- Molecular simulations were employed to model solvent evacuation and stress development in the COF.
- The surface tension of six solvents (DMSO, DMF, acetone, methanol, hexane, perfluorohexane) was correlated with induced contractive stress.
- The mechanical strength of the COF was estimated to predict structural collapse or integrity.
Main Results:
- Solvent evacuation induces contractive stress due to nanocavity formation within the COF.
- Contractive stress magnitude directly correlates with the solvent's surface tension.
- Hexane and perfluorohexane were predicted to enable successful COF activation at 80 °C without structural collapse, unlike the other four solvents.
- Predictions were validated by experimental observations.
Conclusions:
- Solvent cohesive forces, reflected by surface tension, are critical in determining COF structural stability during activation.
- Hexane and perfluorohexane are suitable solvents for activating the studied imine-based COF.
- This work offers fundamental insights into solvent-induced structural collapse and guides the design of stable COFs.
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