A 2D Soft Covalent Organic Framework Membrane Prepared via a Molecular Bridge

Abstract Highly flexible and robust self‐standing covalent organic framework (COF) membranes with rapid preparation are important but technically challenging for achieving precise separation. Herein , 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, is reported. The soft 2D covalent organic framework membrane is rapidly formed (≈5 min) based on the sodium dodecyl sulfate (SDS) molecular channel constructed at the water/dichloromethane (DCM) interface, which is 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 strong alkaline (5 mol L⁻¹ NaOH), acid (0.1 mol L⁻¹ HCl), and various organic solutions, and sufficient flexibility with a large curvature of 2000 m⁻¹ for membrane‐based separation science and technology.