A 2D Soft Covalent Organic Framework Membrane Prepared via a Molecular Bridge

Abstract

Highly flexible and robust self-standing covalent organic framework (COF) membranes with rapid preparation are important but technically challenging for achieving precise separation. Herein , a novel imine-based 2D soft covalent organic framework (SCOF) membrane with a large area of 226.9 cm 2 , via ingeniously selecting an aldehyde flexible linker and a trigonal building block, is reported. The soft 2D covalent organic framework membrane is rapidly formed (≈5 min) based on the sodium dodecyl sulfate (SDS) molecular channel constructed at the water/dichloromethane (DCM) interface, which is the record-fast SCOF membrane formation and 72 times faster than that in the reported literature. MD simulation and DFT calculation elucidate that the dynamic, self-assembled SDS molecular channel facilitates faster and more homogeneous transfer of amine monomers in the bulk, thereby forming a soft 2D self-standing COF membrane with more uniform pores. The formed SCOF membrane exhibits superb sieving capability for small molecules, robustness in strong alkaline (5 mol L −1 NaOH), acid (0.1 mol L −1 HCl), and various organic solutions, and sufficient flexibility with a large curvature of 2000 m −1 for membrane-based separation science and technology.

Colloidal 2D Covalent Organic Framework-Tailored Nanofiltration Membranes for Precise Molecular Sieving

“…The size of the COF nanosheets gradually decreased from 324 to 222 nm, which was attributed to the decrease in the volume of the oil phase, leading to a reduced interface between the two phases and consequently resulting in smaller-sized COF nanosheets. The synthesis efficiency of colloidal COF was evaluated using UV spectroscopy . The system exhibited the most stability when the oil–water volume ratio was 1:8, at which the highest absorbance was obtained (Figure S1).…”

“…The synthesis efficiency of colloidal COF was evaluated using UV spectroscopy. 37 The system exhibited the most stability when the oil−water volume ratio was 1:8, at which the highest absorbance was obtained (Figure S1). With the increase in surfactant concentration (Figure 3b), the emulsion system became more stable, the emulsified droplets were smaller, and the reduction of the emulsified interface between the two phases led to a decrease in the nanosheet size.…”

Two‐Dimensional Conjugated Polymers: a New Choice For Organic Thin‐Film Transistors

“…Inspired by the Chinese fairy tales "Cowherd and Weaver Girl", Liu and his colleagues used SDS molecules as "Magpie Bridges" to accelerate the partitioning of tris (4-aminophenyl) amine at the interface through electrostatic interactions, which contributed the soft COF membrane forming in about five minutes (Figure 4a). [56] The films showed better smoothness compared to those in the no-SDS state. The method also enhanced the polymerization rates and corresponding film properties of butanedial and adipaldehyde, two other molecules in addition to glutaraldehyde, confirming that this strategy paved the way for the synthesis of 2DCP films with the involvement of flexible monomers.…”

Porous crystalline materials for memories and neuromorphic computing systems

“…Recently, Liu et al reported a ''Magpie Bridge'' strategy that was performed by adding surfactants to connect the two monomers in water and organic phases for improving the film crystallinity. 269 Specially, the sodium dodecyl sulfate This journal is © The Royal Society of Chemistry 2023 (SDS) was applied as ''Magpie Bridge'' to connect the TAPA in organic phase and the flexible glutaraldehyde in water phase. Due to the electrostatic attraction between R-SO 3 2À and positively charged TAPA monomers, the TAPA monomers accumulated regularly at the interface of water and organic phases, resulting in enhanced crystallinity, surface smoothness, and mechanical properties.…”

“…The terms ''apparatus accessibility'' and ''professional accessibility'' pertain to the necessary requirement of equipment and professional competence during film fabrication, while high value indicates a lower level of requirement. The coordinate values for each film growth method are estimated comprehensively based on corresponding references, solvothermal, 201,202,[204][205][206][207][208][209]213,219,222,224 VAC, 226-228 continuous flow, 231,232 A-L, [239][240][241][242][243][244]246,247 and L-L 191,252,257,259,[261][262][263][264][265][266][267][268][269] This journal is © The Royal Society of Chemistry 2023 Chem. Soc.…”