Ultra-Low Density Covalent Organic Framework Sponges with Exceptional Compression and Functional Performance

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Covalent organic frameworks (COFs) offer tunable properties but traditional powders are difficult to process.
• The brittleness of COF powders limits the mechanical stability of macroscopic COF objects.
• Developing processable and mechanically stable COF materials is crucial for their practical applications.

Purpose of the Study:

• To synthesize a continuous, hierarchically porous, and mechanically robust COF macroscopic object.
• To overcome the brittleness limitations of conventional COF powders.
• To explore the potential of the developed COF material in various applications.

Main Methods:

• Template-assisted framework synthesis.
• Fabrication of a continuous, interconnected open-cell COF structure with hollow sponge walls.
• Characterization of porous structure, surface area, density, and mechanical stability.

Main Results:

• A COF sponge with hierarchical porosity, high surface area (1655 m² g⁻¹), and ultralow density (2.2 mg cm⁻³) was successfully synthesized.
• The COF sponge exhibited exceptional mechanical stability, retaining over 90% of its stress and height after 300,000 compressions at 50% strain.
• The material demonstrated excellent solvent absorption capacity, catalytic performance, and reusability.

Conclusions:

• The developed template-assisted method enables the creation of mechanically robust COF macroscopic objects.
• This hierarchical porous COF sponge offers a promising platform for advanced applications, overcoming limitations of traditional COF powders.
• The study broadens the development pathway for COF macroscopic objects, unlocking their practical potential.