Enhance Hydrogen Isotopes Separation by Alkali Earth Metal Dopant in Metal–Organic Framework

Kinetic quantum sieving (KQS) based on pore size and chemical affinity quantum sieving (CAQS) based on adsorption site are two routes of porous materials to separate hydrogen isotope mixtures. Alkali earth metals (Be, Mg, and Ca) were doped into UiO-67 to explore whether these metal sites can promote H2/D2 separation. Based on the zero-point energy and adsorption enthalpy calculated by density functional theory calculations, the Be dopant shows better H2/D2 separation performance than other alkali earth metal dopants and unsaturated metal sites in metal–organic frameworks based on CAQS. Orbital interaction strongly relates to the chemical affinity and further influences the D2/H2 selectivity. Moreover, the predicted D2/H2 selectivity of Be-doped sites (49.4) at 77 K is even larger than the best experimental result (26). Finally, the different dynamic behaviors of H2 and D2 on Be-doped UiO-67 indicate its strong H2/D2 separation performance via KQS

Synthesis and Self-Assembly of Large-Area Cu Nanosheets and Their Application as an Aqueous Conductive Ink on Flexible Electronics

Large-area Cu nanosheets are synthesized by a strategy of Cu nanocrystal self-assembly, and then aqueous conductive Cu nanosheet ink is successfully prepared for direct writing on the conductive circuits of flexible electronics. The Cu nanocrystals, as building blocks, self-assemble along the ⟨111⟩ direction and grow into large-area nanosheets approximately 30–100 μm in diameter and a few hundred nanometers in thickness. The laminar stackable patterns of the Cu nanosheet circuits increase the contact area of the Cu nanosheets and improve the stability of the conductor under stress, the result being that the Cu nanosheet circuits display excellent conductive performance during repeated folding and unfolding. Moreover, heterostructures of Ag nanoparticle-coated Cu nanosheets are created to improve the thermal stability of the nanosheet circuits at high temperatures

Vacuum-Dried Synthesis of Low-Density Hydrophobic Monolithic Bridged Silsesquioxane Aerogels for Oil/Water Separation: Effects of Acid Catalyst and Its Excellent Flexibility

Low-density hydrophobic monolithic bridged silsesquioxane aerogels were prepared by vacuum drying using terephthalaldehyde (TPAL) and 3-aminopropyl-triethoxysilane (APTES) as precursors and acetic acid as catalyst. The effects of acid on the vacuum-dried synthesis of bridged silsesquioxane aerogels were investigated. The results indicate that the growth mechanism changes from cluster–cluster to monomer–cluster when acid is added, which induces the formation of the low-density monolithic aerogels with increased pore size. The methyltrimethoxysilane (MTMS) co-precursor could endow the aerogels with good hydrophobicity. The densities, pore structure, hydrophobicity, and mechanical properties of the obtained bridged silsesquioxane aerogels were investigated in detail. The results show that the monolithic aerogels possess low density (0.071 g/cm³), high hydrophobicity (contact angle, >140°), and excellent flexibility (Young’s modulus, 0.029 MPa). All of these characteristics make the hydrophobic aerogels competitive candidates for oil/water separation

Vacuum-Dried Synthesis of Low-Density Hydrophobic Monolithic Bridged Silsesquioxane Aerogels for Oil/Water Separation: Effects of Acid Catalyst and Its Excellent Flexibility

Low-density hydrophobic monolithic bridged silsesquioxane aerogels were prepared by vacuum drying using terephthalaldehyde (TPAL) and 3-aminopropyl-triethoxysilane (APTES) as precursors and acetic acid as catalyst. The effects of acid on the vacuum-dried synthesis of bridged silsesquioxane aerogels were investigated. The results indicate that the growth mechanism changes from cluster–cluster to monomer–cluster when acid is added, which induces the formation of the low-density monolithic aerogels with increased pore size. The methyltrimethoxysilane (MTMS) co-precursor could endow the aerogels with good hydrophobicity. The densities, pore structure, hydrophobicity, and mechanical properties of the obtained bridged silsesquioxane aerogels were investigated in detail. The results show that the monolithic aerogels possess low density (0.071 g/cm³), high hydrophobicity (contact angle, >140°), and excellent flexibility (Young’s modulus, 0.029 MPa). All of these characteristics make the hydrophobic aerogels competitive candidates for oil/water separation

Synthesis of Heparin-Immobilized, Magnetically Addressable Cellulose Nanofibers for Biomedical Applications

Magnetically responsive heparin-immobilized cellulose nanofiber composites were synthesized by wet-wet electrospinning from a nonvolatile, room-temperature ionic liquid (RTIL), 1-methyl-3-methylimidazolium acetate ([EMIM]­[Ac]), into an aqueous coagulation bath. Superparamagnetic magnetite (Fe₃O₄) nanoparticles were incorporated into the fibers to enable the manipulation of both dry and wet nanofiber membranes with an external magnetic field. Three synthetic routes were developed to prepare three distinct types of nanocomposite fibers: cellulose-Fe₃O₄–heparin monofilament fibers, cellulose-Fe₃O₄–heparin core–shell fibers with heparin covalently immobilized on the fiber surface, and cellulose -Fe₃O₄ core–shell fibers with heparin physically immobilized on the fiber surface. These nanocomposite fibers were characterized by electron microscopy to confirm their coaxial structure and the fiber dimensions (fiber diameter 0.2–2.0 μm with 0.1–1.1 μm core diameter). Thermogravimetric analysis, liquid chromatography–mass spectrometry, Fourier transform infrared and X-ray diffraction spectroscopy provided detailed compositional analysis for these nanocomposite fibers, confirming the presence of each component and the surface accessibility of the heparin. The anticoagulant activity of immobilized heparin on the nanocomposite fiber surfaces was evaluated and confirmed by antifactor Xa and antifactor IIa assays

A Facile in Situ Self-Assembly Strategy for Large-Scale Fabrication of CHS@MOF Yolk/Shell Structure and Its Catalytic Application in a Flow System

A hierarchical yolk/shell copper hydroxysulfates@MOF (CHS@MOF, where MOF = metal–organic frameworks) structure was fabricated from a homogeneous yolk/shell CHS template composed of an active shell and a stabilized core via a facile self-template strategy at room temperature. The active shell of the template served as the source of metal ion and was in situ transformed into a well-defined MOF crystal shell, and the relatively stabilized core retained its own nature during the formation of the MOF shell. The strategy of in situ transformation of CHS shell to MOF shell avoided the self-nucleation of MOF in the solution and complex multistep procedures. Furthermore, a flow reaction system using CHS@MOF as self-supported stationary-phase catalyst was developed, which demonstrated excellent catalytic performance for aldehyde acetalization with ethanol, and high yields and selectivities were achieved under mild conditions

Biodegradable and Bioactive PCL–PGS Core–Shell Fibers for Tissue Engineering

Poly­(glycerol sebacate) (PGS) has increasingly become a desirable biomaterial due to its elastic mechanical properties, biodegradability, and biocompatibility. Here, we report microfibrous core–shell mats of polycaprolactone (PCL)–PGS prepared using wet–wet coaxial electrospinning. The anticoagulant heparin was immobilized onto the surface of these electrospun fiber mats, and they were evaluated for their chemical, mechanical, and biological properties. The core–shell structure of PCL–PGS provided tunable degradation and mechanical properties. The slowly degrading PCL provided structural integrity, and the fast degrading PGS component increased fiber elasticity. Young’s modulus of PCL–PGS ranged from 5.6 to 15.7 MPa. The ultimate tensile stress ranged from 2.0 to 2.9 MPa, and these fibers showed elongation from 290 to 900%. The addition of PGS and grafting of heparin improved the attachment and proliferation of human umbilical vein endothelial cells. Core–shell PCL–PGS fibers demonstrate improved performance as three-dimensional fibrous mats for potential tissue-engineering applications