Rationally engineering interfacial polymerization toward covalent organic framework membranes mediated by ionic liquids

Liquid–liquid interfacial polymerization (IP) serves as a facile method for fabricating covalent organic framework (COF) membranes, while designing task‐specific IP systems remains a huge challenge. This work proposes a rational strategy to achieve controlled IP by monomer–catalyst–biphasic solvents matching, integrating thermodynamic predictions and dynamic insights. For the IP engineering, ionic liquids (ILs) are introduced into the biphasic solvent system due to their unique physicochemical properties. Utilizing conductor‐like screening model for realistic solvents (COSMO‐RS) calculations, deep learning‐aided physical properties predictions, and molecular dynamics simulations, 10 promising pairs were identified from 622 candidates. This strategy enables the transition from highly cross‐linked amorphous membranes to uniform crystalline membranes with reduced thickness (from 520 to 124 nm), synergizing thermodynamic partition and diffusion regulation. The membranes exhibit increased water permeance (from 0.022 to 7.43 L·m −2 ·h −1 ·bar −1 ) and high antibiotic desalination efficiency. Furthermore, this strategy is successfully extended to other COF membranes, enriching the tuning flexibility of IP system for the development of novel COF membranes.