Molecularly soldered covalent organic frameworks for ultrafast precision sieving
Yanqiu Zhang1,2, Jing Guo1, Gang Han3
1MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, State Key Laboratory of Urban Water Resource and Environment, and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
Science Advances
|March 25, 2021
Summary
This study introduces a novel method to create defect-free covalent organic framework (COF) membranes using dopamine. These advanced COF membranes offer superior precision sieving for molecular and ion separation.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Covalent organic framework (COF) nanocrystals have weak interlamellar interactions, hindering the development of efficient ion/molecular sieving membranes.
- Defects and stability issues in stacked COF membranes lead to poor contaminant selectivity.
Purpose of the Study:
- To develop a facile in situ molecularly soldered strategy for fabricating defect-free ultrathin COF membranes.
- To enhance the sieving abilities and mechanical properties of COF membranes for precise separation.
Main Methods:
- In situ molecularly soldered strategy combining COF condensation polymerization and dopamine self-polymerization.
- Density functional theory (DFT) simulations to understand reaction mechanisms.
- Fabrication of ultrathin COF membranes.
Main Results:
- Dopamine polymerization generates reactive oxygen species that catalyze COF nucleophilic reactions, promoting thin layer growth.
- Dopamine effectively solders COF crystals, eliminating defects and improving mechanical strength.
- The resulting COF membranes demonstrate ultrafast precision sieving for molecular and ion removal in various solvents.
Conclusions:
- The developed strategy successfully creates defect-free, ultrathin COF membranes with enhanced mechanical properties.
- These novel COF membranes exhibit superior performance in molecular separation and ion removal compared to existing state-of-the-art membranes.
