Using melt polymerization to fabricate robust covalent organic framework foams

Adsorption-based (e.g., gas or liquid molecules) separation technologies have shown unique economic and environmental advantages in specific applications. In industrial applications, ideal high-efficiency adsorbents require not only high adsorption capacity/selectivity, but also good machinability, cycling, and mechanical stability. Thus, it is necessary to assemble the adsorbents into high-stability monoliths (e.g., spheres, membranes, aerogels, etc.). Recently, COFs, as an emerging class of advanced adsorbents, have demonstrated many heartening performances in numerous separation fields. However, most of the state-of-the-art COF adsorbents still suffer from issues such as low processability (mostly existing as microcrystalline powders), lack of stability (mostly built by the reversible bond linkages), and difficulty for scalable synthesis. Therefore, it is of great significance to create new strategies to produce highly robust COF monoliths (e.g., porous foams) for practical applications.