Flexible, Mechanically Stable, Porous Self‐Standing Microfiber Network Membranes of Covalent Organic Frameworks: Preparation Method and Characterization

Abstract Covalent organic frameworks (COFs) show advantageous characteristics, such as an ordered pore structure and a large surface area for gas storage and separation, energy storage, catalysis, and molecular separation. However, COFs usually exist as difficult‐to‐process powders, and preparing continuous, robust, flexible, foldable, and rollable COF membranes is still a challenge. Herein, such COF membranes with fiber morphology for the first time prepared via a newly introduced template‐assisted framework process are reported. This method uses electrospun porous polymer membranes as a sacrificial large dimension template for making self‐standing COF membranes. The porous COF fiber membranes, besides having high crystallinity, also show a large surface area (1153 m 2 g −1 ), good mechanical stability, excellent thermal stability, and flexibility. This study opens up the possibility of preparation of large dimension COF membranes and their derivatives in a simple way and hence shows promise in technical applications in separation, catalysis, and energy in the future.