Solvent-vapor-assisted crystallization of covalent organic framework films for CO2/CH4 separation

Covalent organic framework films were prepared using alternating vapor deposition of precursors followed by solvent vapor annealing. When an as-deposited film was annealed in appropriate solvent vapors, the prepared covalent organic framework film exhibited an “onion-like” structure. This result opens a way to synthesize covalent organic framework films with highly ordered planar layers through the interaction between layers. The CO2/CH4 separation performance of covalent organic framework film was significantly improved due to the decrease in defects caused by crystallization.