2D Soft Covalent Organic Framework Membrane Prepared via Molecular Bridge.

Highly flexible and robust self-standing covalent organic framework (COF) membranes with rapid preparation are important but technically challenging for achieving precise separation. In this contribution, we first report a novel imine-based 2D soft covalent organic framework (SCOF) membrane with a large area of 226.9 cm2 via ingeniously selecting an aldehyde flexible linker and a trigonal building block. The soft 2D covalent organic framework membrane was rapidly formed (approximately 5 min) based on the sodium dodecyl sulfate (SDS) molecular channel constructed at the water/dichloromethane (DCM) interface, which was the record-fast SCOF membrane formation and 72 times faster than that in the reported literature. MD simulation and DFT calculation elucidate that the dynamic, self-assembled SDS molecular channel facilitates faster and more homogeneous transfer of amine monomers in the bulk, thereby forming a soft 2D self-standing COF membrane with more uniform pores. The formed SCOF membrane exhibits superb sieving capability for small molecules, robustness in (I) strong alkaline (5 mol/L NaOH), (II) acid (0.1 mol/L HCl), and (III) various organic solutions, and sufficient flexibility with a large curvature of 2000 m-1 for membrane-based separation science and technology. This article is protected by copyright. All rights reserved.