Jie Zhang,Xiaofeng Li,Feng Yang,Zhengdong Ouyang,Pan He,Zhimin Jia,Honghan Long,Ningning He,Yingdan Zhang,Yingdi Zou,Bo Jiang,Ziqian Han,Guohong Tao,Ning Liu,Yang Li,Lijian Ma
The efficient preparation of two-dimensional large-sized monolayer covalent organic framework (COF) nanosheets for highly permeable membranes has posed a long-standing challenge in the COF field. While the self-exfoliation of charged COFs represents a promising method for nanosheet production, its efficiency requires further enhancement. In this study, we present a novel finding that the presence of hydroxyl groups on the monomer significantly influences the self-exfoliation efficiency of charged COFs. Through precise regulation of hydroxyl group numbers on the monomers, we successfully achieved the efficient fabrication of large monolayer cationic COF nanosheets with impressive solubilities in common organic solvents. By virtue of their positive charge, COF monolayer nanosheets rapidly interacted with negatively charged monolayer graphene oxide (GO) in solution, facilitating their assembly into interlaced composite membranes through electrostatic interactions. The composite membranes benefited from the strong Coulombic attraction between the COF and GO nanosheets, leading to enhanced membrane stability, while the shielding effect of GO on the COF pores contributed to improved size sieving efficiency. This innovative strategy enabled the composite membranes to achieve highly selective separation of ReO4– and MoO42–, with a remarkable 100% interception rate for MoO42–.
Biomimetic synthesis represents a cutting-edge topic in chemistry/materials science. Herein, we demonstrate poly(ethylene glycol) (PEG) short side-chain-assisted monomer complex coacervation and reaction-induced polyion complex compartmentalization that lead to oxygen-tolerant polymerization-induced electrostatic self-assembly (PIESA). This is achieved by the one-pot synthesis of a PEGylated anionic polyelectrolyte and heterogeneous iterative polymerization of a cationic monomer under ecofriendly ambient, in-air aqueous photo-RAFT conditions. Simultaneous reversible all-segment-participating ternary complex coacervation and Coulombic interdomain interactions lead to coacervate nanoreactors that are capable of immediate initiation and fast reversible addition–fragmentation chain transfer reactions. Approximately 2 nm monomer complex nanoclusters act as building blocks to drive liquid–liquid phase separation. Polymerization induces hierarchical self-assembly in a droplet nucleation–fusion–fission mechanism together with PEG-crowded polyion complex compartmentalization, using nanoclusters as building blocks, mechanistically similar to liquid–liquid phase separation through supramolecular polymerization. Consequently, protein-like, one-component multicompartment coacervate nanoreactors with oxygen-tolerant well-controlled fast reactions are achieved. This work provides important implications for the efficient precise synthesis of biomimetic coacervate nanodevices of increasing complexity.
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