Epitaxially Grown Mechanically Robust 2D Thin Film of Secondary Interactions Led Molecularly Woven Material.

Molecularly woven materials with striking mechanical resilience, and 2D controlled topologies like textiles, fishing nets, and baskets are highly anticipated. Molecular weaving exclusively apprehended by the secondary interactions expanding to laterally grown 2D self-assemblies with retained crystalline arrangement is stimulating. The interlacing entails planar molecules screwed together to form 2D woven thin films. Here, secondary interactions led 2D interlaced molecularly woven material (2° MW) built by 1D helical threads of organic chromophores twisted together via end-to-end CH···O connections, held strongly at inter-crossing by multiple OH···N interactions to prevent slippage is presented. Whereas, 1D helical threads with face-to-face O-H···O connections sans interlacing led the non-woven material (2° NW). The polarity-driven directionality in 2° MW led the water-actuated epitaxial growth of 2D-sheets to lateral thin films restricted to nano-scale thickness. The molecularly woven thin film is self-healing, flexible, and mechanically resilient in nature, while maintaining the crystalline regularity is attributed to the supple secondary interactions (2° ).

Biomimetic Helical Hydrogen Bonded Organic Framework Membranes for Efficient Uranium Recovery from Seawater.

Inspired by the uranyl-imidazole interactions via nitrogen's (N's) of histidine residues in single helical protein assemblies with open framework geometry that allows through migration/coordination of metal ions. Here, preliminary components of a stable hydrogen-bonded organic framework (HOF) are designed to mimic the stable single helical open framework with imidazole residues available for Uranium (U) binding. The imidazolate-HOF (CSMCRIHOF2-S) is synthesized with solvent-directed H-bonding in 1D array and tuned hydrophobic CH-π interactions leading to single helix pattern having enhanced hydrolytic stability. De-solvation led CSMCRIHOF2-P with porous helical 1D channels are transformed in a freestanding thin film that showcased improved mass transfer and adsorption of uranyl carbonate. CSMCRIHOF2-P thin film can effectively extract ≈14.8 mg g-1 in 4 weeks period from natural seawater, with > 1.7 U/V (Uranium to Vanadium ratio) selectivity. This strategy can be extended for rational designing of hydrolytically stable, U selective HOFs to realize the massive potential of the blue economy toward sustainable energy.

Fabrication of microporous polyaryl nanofilm at the liquid-liquid interface for selective molecular separation.

Polymeric membranes with precise molecular weight cutoffs are necessary for molecular separations. Here, we present a stepwise preparation of microporous polyaryl (PAR_TTSBI) freestanding nanofilm as well as the synthesis of bulk polymer (PAR_TTSBI) and fabrication of thin film composite (TFC) membrane, with crater-like surface morphology, then provide the details of separation study of PAR_TTSBI TFC membrane. For complete details on the use and execution of this protocol, please refer to Kaushik et al. (2022)1 and Dobariya et al. (2022).2.

Protocol for the synthesis and use of U selective hydrogen-bonded organic framework to prepare large-area free-standing thin film.

Hydrogen-bonded organic frameworks (HOFs) are assembled via non-covalent secondary interactions that are scintillating examples of porous crystalline materials. This protocol highlights the synthesis and characterization of U selective, permanently porous, hydrolytically stable single-component CSMCRIHOF-1. We describe the steps to synthesize hydrogen bonding motif and single crystals of CSMCRIHOF-1. We then detail the preparation of large-area free-standing thin film of CSMCRIHOF-1 (TFCH). Finally, we describe the assessment of the hydrolytic stability of CSMCRIHOF-1 and TFCH. For complete details on the use and execution of this protocol, please refer to Kaushik et al. (2022).1.

Protocol for extraction, characterization, and computational analysis of uranium from seawater.

Here, we present a protocol for uranium extraction from seawater (UES) and its characterization and computational-based structure analysis. We describe formulating batch adsorption experiments for adsorptive separation of uranium using thin film (TFCH) of Hydrogen-bonded Organic Framework (CSMCRIHOF-1). We then detail the recovery of uranium using eluent mixtures and the steps to regenerate TFCH for recyclability studies. Finally, we describe the spectroscopic characterizations of TFCH and uranium adsorbed TFCH, followed by computational analysis of the structures and binding sites. For complete details on the use and execution of this protocol, please refer to Kaushik et al. (2022).1.

Perm-selective ultrathin high flux microporous polyaryl nanofilm for molecular separation.

Polymeric membranes with high permeance and selectivity performances are anticipated approach for water treatment. Separation membranes with moderate molecular weight cut-offs (MW in between 400 and 700 g mol-1) are desirable to separate multivalent ions and small molecules from a water stream. This requires polymeric membranes with controlled pore, pore size distribution, surface charge, and thin active layer to maximize membrane performance. Here, a fabrication of the polyaryl nanofilm with thickness down to ∼15 nm synthesized using interfacial polymerization onto ultrafiltration supports is described. Electron microscopy analysis reveals the presence of crumpled surface morphology in polyaryl nanofilm. Polyaryl nanofilm shows high water permeance of ∼110 Lm-2h-1 bar-1. Polyaryl nanofilm presents molecular weight cut-off greater than ∼450 gmol-1 (molecular marker) with water permeance of ∼84 Lm-2h-1 bar-1. Multivalent salt (K3[Fe(CN)6]) has higher rejection (>95%) as compared to the monovalent (∼5%) and divalent salt (∼28%) with the water permeance of ∼81 Lm-2h-1 bar-1.