Molecularly soldered covalent organic frameworks for ultrafast precision sieving

Abstract

The weak interlamellar interaction of covalent organic framework (COF) nanocrystals inhibit the construction of highly efficient ion/molecular sieving membranes owing to the inferior contaminant selectivity induced by defects in stacked COF membranes and stability issues. Here, a facile in situ molecularly soldered strategy was developed to fabricate defect-free ultrathin COF membranes with precise sieving abilities using the typical chemical environment for COF condensation polymerization and dopamine self-polymerization. The experimental data and density functional theory simulations proved that the reactive oxygen species generated during dopamine polymerization catalyze the nucleophilic reactions of the COF, thus facilitating the counter-diffusion growth of thin COF layers. Notably, dopamine can eliminate the defects in the stacked COF by soldering the COF crystals, fortifying the mechanical properties of the ultrathin COF membranes. The COF membranes exhibited ultrafast precision sieving for molecular separation and ion removal in both aqueous and organic solvents, which surpasses that of state-of-the-art membranes.

Barrier, rheological, and antimicrobial properties of sustainable nanocomposites based on gellan gum/polyacrylamide/zinc oxide

“…The characteristic polyacrylamide peaks at 3344, 3179, 2944, 1654, 1605, and 1319 cm −1 correspond to NH 2 stretching, NH bending, CH 2 CH stretching, C═O stretching (amide 1), NH 2 bending (amide II), and CN stretching, respectively. [ 1,6‐7 ] The peaks appeared at 2924, 2822, and 1650 cm −1 represent the CH and C═O stretching of the carboxylate groups. The characteristic bands at 1415 and 1708 cm −1 are due to the CH stretching of the methyl groups and C═O stretching of the allyl ester.…”

“…Therefore, considerable efforts are being made to produce biodegradable packaging materials with long lifetime from sustainable materials or resources. [ 1‐7 ] Polysaccharide‐, protein‐, and lipid‐based composites have been studied for packaging applications. But these materials obtained from natural resources have relatively poor mechanical and barrier properties.…”

Macroscopic covalent organic framework architectures for water remediation

“…It is noteworthy to mention that the number of reports of COFs and their hybrid versions for water treatment has been drastically increased in a last few year due to the potential features of the material. [150][151][152][153][154] The macroscopic architecture of COF is a promising research area, especially in water remediation technology. However, we believe, this field is still at the early stage and has vast opportunity to go beyond that.…”

The Journey of Water Remediation through Biomimetic Strategies: A Mechanistic Insight

“…fabricated an ultrathin, highly selective PDA‐based covalent–organic framework (COF) membrane. [ 100 ] The membranes had excellent antifouling characteristics and rejected 99.5% of Na 2 SO 4 . The water permeance value for the membranes was about 53.1 LMH bar −1 .…”