Deep Eutectic Solvent-Water Interfacial Polymerization: A Scalable Route to Tailorable Covalent Organic Framework...

Area of Science:

• Materials Science
• Chemical Engineering
• Membrane Science

Background:

• Synthesizing large-area, ordered covalent organic framework (COF) membranes with high flux and selectivity is challenging.
• Existing methods struggle with scalability and controlling membrane properties.

Purpose of the Study:

• To develop a scalable platform for fabricating high-performance COF membranes.
• To investigate the role of deep eutectic solvents (DES) in controlling COF membrane formation.

Main Methods:

• Utilized a deep eutectic solvent (DES)-water system to suppress the Marangoni effect and tailor interfacial properties.
• Employed a "bilateral constraint" strategy using DES viscosity and hydrogen bonding to control monomer diffusion.
• Adjusted the Brønsted acidity of DES to modulate nucleation and reaction kinetics for slow polycondensation.

Main Results:

• Successfully fabricated freestanding, crystalline COF membranes with scalable production up to 600 cm².
• Achieved membranes with a periodic 1D open porous structure.
• Demonstrated high selectivity for antibiotic and dye separations with unprecedented water permeance (307.5 L m^-2 h^-1 bar^-1).

Conclusions:

• The DES-water platform enables scalable, controlled synthesis of advanced COF membranes.
• The developed membranes offer superior performance for separation applications.
• This work advances interfacial polymerization for robust, crystalline membrane production.