Ultralight and Robust Covalent Organic Framework Fiber Aerogels

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Shaping covalent organic frameworks (COFs) into macroscopic objects with robust mechanical properties and hierarchical porosity is crucial for practical applications.
• Existing methods for creating macroscopic COFs face significant challenges in scalability and achieving desired structural integrity.

Purpose of the Study:

• To develop a general and scalable protocol for preparing ultralight and robust pure COF fiber aerogels (FAGs).
• To investigate the structural, mechanical, and absorption properties of the fabricated COF FAGs.

Main Methods:

• Utilized an epitaxial growth synergistic assembly (EGSA) strategy.
• In situ growth of COF nanofibers on electrospun polyacrylonitrile (PAN) microfibers containing urea-based linkers.
• Removal of PAN via solvent extraction to yield hollow COF microfibers.

Main Results:

• Successfully fabricated ultralight COF FAGs with densities between 14.1-15.5 mg cm⁻³.
• Achieved hierarchical porosity (micro-, meso-, and macropores) and excellent mechanical properties, including full recovery at 50% strain.
• Demonstrated high organic solvent absorption capacity, with chloroform uptake exceeding 90 g g⁻¹.

Conclusions:

• The EGSA strategy provides a scalable route to macroscopic COFs with desirable properties.
• The resulting COF FAGs exhibit superior mechanical robustness and absorption capabilities.
• This work opens new avenues for designing and fabricating advanced macroscopic COF materials.