Turing COF Membranes with Tunable Patterns for Antibiotic Desalination.

Tailorable membrane surface architectures are crucial for efficient and precise separation. The nanoemulsion regulation strategy, an emerging technique for constructing nanostructured membranes with tunable architectures, has been scarcely explored for the fabrication of covalent organic framework (COF) membranes. In this work, inspired by the vesicle storage, transport, and release mechanism in human cells and the natural self-assembly of emulsions at interfaces, we proposed a nanoemulsion-directed interfacial polymerization (NDIP) strategy to precisely construct COF membranes with tunable Turing patterns. The introduction of these Turing structures leads to COF membranes with fewer defects and an enlarged surface area, attributable to the nanoemulsion templating effect and the controlled monomer transport mechanism. Short-range van der Waals forces and electrostatic interactions between the nanoemulsions and monomers were elucidated through molecular dynamics simulations and experimental results. Moreover, we systematically explored the effects of variable nanoemulsification space, different internal microenvironments, and emulsifier chain length on membrane separation performance. The designed Turing COF membranes exhibit excellent antibiotic separation ability with a molecular weight cutoff of 289 g/mol and ultrahigh antibiotic/salt selectivity (124.1 for TC/NaCl). This study provides a new design perspective for patterned regulation in COF membranes and highlights the potential of emulsion-guided strategies for advanced molecular separations.