Hydrogen‐bonded organic framework membranes through dispersion‐controlled deposition method for efficient CO2 separation

Abstract Hydrogen‐bonded organic frameworks (HOFs) feature a highly ordered pore structure, abundant organic functional groups, and unique solution‐processability, holding great promise in gas separations. In this study, we explored the fabrication of HOF membranes utilizing a dispersion‐controlled deposition (DCD) method. To achieve homogeneous dispersion, the bulk HOF aggregates were initially dispersed in solvent and then switched to anti‐solvent to generate the precipitated nanoparticles. Under vacuum‐assisted assembly, the HOF colloidal solution containing nanoparticles was uniformly deposited, and the intracrystalline defects were spontaneously healed during the mixed‐solvent evaporation. For the first time, HOF polycrystalline membranes were fabricated on flexible polymer substrates and demonstrated an ultrathin HOF selective layer of ~100 nm. The prepared HOF membranes exhibited high separation performance, with the CO 2 permeance exceeding 600 GPU and the CO 2 /N 2 selectivity exceeding 30. This work establishes a platform technology for HOF membrane fabrication and expands the families of carbon capture membranes.