Amphiphilic Reactive Interfaces Enable Controlled Synthesis of Mesoscopic Covalent Organic Frameworks

Interfaces serve as powerful, versatile platforms that have significantly advanced the development of novel materials. However, bottom-up construction of reactive interfaces for controlled synthesis of crystalline porous materials still remains a substantial challenge. Here, we constructed a stable, morphology-tunable reactive interface by spontaneous self-assembly of amphiphilic moiety derived from Schiff base reactions, featuring the surfactant-free stabilization and versatile interface morphology readily adjusted by hydrophobic chain length (C4-C12) of aliphatic amines. Such interface confinement lowers nucleation barriers while the localized monomer enrichment speeds reactions, thus enabling a mild, facile, and controlled synthesis of covalent organic frameworks (COFs) with diverse mesoscopic architectures (spherical/ribbon/sheet). Further introducing colloidal SiO₂ nanospheres on the interfaces can co-assemble and form stable nanoscale Pickering emulsions, yielding hierarchical porous COFs with tunable, large mesopores (17-40 nm) beyond the intrinsic pore size limitation. The resulting asymmetric hemispherical hollow mCOF_PEA (BET surface area of 561.9 m² g^-1) as a potential iodine host (30.18 wt.% loading) delivered remarkable electrochemical performance with an initial capacity of 202.9 mAh g^-1 (96.16% of theoretical value) and retained 132.8 mAh g^-1 after 2500 cycles, profited from their mesoporosity and asymmetric morphology with an increased surface area, exposed more active sites and enhanced ion transport ability.