Dopamine/Silica Nanoparticle Assembled, Microscale Porous Structure for Versatile Superamphiphobic Coating

Artificial superamphiphobic surfaces, which could repel both water and low surface tension organic liquids, have been limited to particular kinds of materials or surfaces thus far. In this work, a kind of microscale porous coating was developed. Taking dopamine and hydrophilic fumed silica nanoparticles as initial building blocks, microscale porous coating was constructed <i>via</i> ice templation. Polydopamine bound silica nanoparticles together to form a porous structure network and rendered the coating to have potential for further postfunctionalization. After two-step CVD, the microscale porous coating changes from superhydrophilic to superamphiphobic, exhibiting super-repellency to droplets with surface tension of 73–23 mN/m. The influences of concentration of initial dopamine, hydrophilic fumed silica nanoparticles, and dry conditions on the formation of the porous structure have been studied to optimize the conditions. Coatings with different pore sizes and pore heights have been fabricated to discover the relationship between the structure parameters and the repellency of the porous coatings. Only with optimal pore size and pore height can the porous coating display superamphiphobicity. Compared with nanoscale, the microscale structure favors the achievement of superamphiphobicity. Given the outstanding adhesive ability of polydopamine, the superamphiphobic coatings have been successfully applied to various materials including artificial materials and natural materials

A Clear Insight into the Distinguishing CO₂ Capture by Two Isostructural Dy^III–Carboxylate Coordination Frameworks

Two isostructural <i><b>the</b></i>-type Dy^III coordination networks were successfully constructed based on a pair of analogous tribenzoate bridging ligands with phenyl and triazinyl central spacers. Notably, the active triazinyl group can obviously enhance the capability and selectivity of CO₂ sorption for the porous framework

Stable Layered Semiconductive Cu(I)–Organic Framework for Efficient Visible-Light-Driven Cr(VI) Reduction and H₂ Evolution

Metal–organic frameworks (MOFs) have gained tremendous attention in the fields of environmental restoration and sustainable energy for their potential use as photocatalyst. Herein, a new two-dimensional (2D) Cu­(I)-based MOF material showing a narrow forbidden-band of 2.13 eV was successfully constructed using a visible-light-harvesting anthracene-based bipyridine ligand. The as-prepared MOF demonstrates high chemical stability and could be stable in the pH range 2–13, which is favorable for its potential application in photocatalysis. Photocatalytic experiments demonstrate that this Cu­(I)-MOF exhibits high reactivity for reduction of Cr­(VI) in water, with 95% Cr­(VI) converting to Cr­(III) in 10 min by using MeOH as scavenger under visible-light illumination. Furthermore, this MOF could behave as a highly active photocatalyst for H₂ evolution without additional photosensitizers and cocatalyst. Remarkably, the as-prepared MOF shows enhanced photocatalytic Cr­(VI) reduction and H₂ evolution performances compared with the pristine light-harvesting ligand under the same conditions. In connection to these, the photocatalytic reaction mechanism has also been probed

Boundary Lubrication by Associative Mucin

Mucus lubricants are widely distributed in living organisms. Such lubricants consist of a gel structure constructed by associative mucin. However, limited tribological studies exist on associative mucin fluids. The present research is the first to investigate the frictional behavior of a typical intact vertebrate mucin (loach skin mucin), which can recover the gel structure of mucus via hydrophobic association under physiological conditions (5–10 mg/mL loach skin mucin dissolved in water). Both rough hydrophobic and hydrophilic polydimethylsiloxane (PDMS) rubber plates were used as friction substrates. Up to 10 mg/mL loach skin mucin dissolved in water led to a 10-fold reduction in boundary friction of the two substrates. The boundary-lubricating ability for hydrophilic PDMS decreased with rubbing time, whereas that for hydrophobic PDMS remained constant. The boundary-lubricating abilities of the mucin on hydrophobic PDMS and hydrophilic PDMS showed almost similar responses toward changing concentration or sodium dodecyl sulfate (SDS). The mucin fluids reduced boundary friction coefficients (μ) only at concentrations (<i>c</i>) in which intermucin associations were formed, with a relationship shown as μ ∼ <i>c</i>^–0.7. Destroying intermucin associations by SDS largely impaired the boundary-lubricating ability. Results reveal for the first time that intermolecular association of intact mucin in bulk solution largely enhances boundary lubrication, whereas tightly adsorbed layer plays a minor role in the lubrication. This study indicates that associated mucin should contribute considerably to the lubricating ability of biological mucus in vivo

Dual-Emitting Dye@MOF Composite as a Self-Calibrating Sensor for 2,4,6-Trinitrophenol

An anionic metal–organic framework (MOF) {(NH₂Me₂)­[Zn₃(μ₃-OH)­(tpt)­(TZB)₃]­(DMF)₁₂}_<i>n</i> (<b>1</b>, tpt = 2,4,6-tri­(4-pyridyl)-1,3,5-triazine, H₂TZB = 4-(1<i>H</i>-tetrazol-5-yl)­benzoic acid and DMF = <i>N</i>,<i>N</i>-dimethylformamide), with both nanosized cages and partitions, has been solvothermally synthesized, which can serve as a crystalline vessel to encapsulate the fluorescent dye rhodamine 6G (Rh6G) via a “bottle around ship” approach. As a result, the obtained dye@MOF composite system features a blue emission of the ligand at 373 nm and a red emission of Rh6G at 570 nm when dispersed in solution, which could be used for decoding the trace amount of 2,4,6-trinitrophenol (TNP) by referring the peak-height ratio of each emission, even in coexistence with other potentially competitive nitroaromatic analytes. Furthermore, the observed fluorescence responses of the composite toward TNP are highly stable and reversible after recycling experiments. To the best of our knowledge, this is the first example of an MOF-implicated self-calibrated sensor for TNP detection

Two Isostructural Coordination Polymers Showing Diverse Magnetic Behaviors: Weak Coupling (Ni^II) and an Ordered Array of Single-Chain Magnets (Co^II)

Two isomorphic 3-D complexes with the formulas [M₃(TPTA) (OH)₂(H₂O)₄]_<i>n</i> (M = Ni for <b>1</b> and Co for <b>2</b>; H₄TPTA = [1,1′:4′,1″-terphenyl]-2′,3,3″,5′-tetracarboxylic acid) have been synthesized and magnetically characterized. Complexes <b>1</b> (Ni^II) and <b>2</b> (Co^II) have the same 1-D rod-shaped inorganic SBUs but exhibit significantly different magnetic properties. Complex <b>2</b>(Co^II) is a 3-D arrangement of a 1-D Co^II single-chain magnet (SCM), while complex <b>1</b>(Ni^II) exhibits weak coupling

Coordination Assembly of Zn^II/Cd^II Terephthalate with Bis-Pyridinecarboxamide Tectons: Establishing Net Entanglements from [3 + 3] Interpenetration to High-Connected Self-Penetration

Four polymeric d¹⁰ metal terephthalate complexes incorporating bis-pyridinecarboxamide building blocks were prepared to explore the effect of the central metal ion or the fluorine substituent of the ligand on the topology and entanglement of coordination networks. The combination of Zn^II terephthalate with a fluorinated ligand leads to a noninterpenetrated coordination layer with honeycomb (hcb) topology for complex <b>1</b>. Interestingly, the other three materials display the unusual entangling coordination networks. For <b>2</b>, the reaction of zinc terephthalate with nonfluorinated ligand affords three-dimensional diamond (dia) architecture of [3 + 3] interpenetration, while the Cd^II terephthalate complexes <b>3</b> and <b>4</b> with the two types of bis-pyridinecarboxamide tectons show the isostructural self-penetrating framework with unique 8-connected (4¹⁷.6¹¹) topology

Controlled Crystal Transformations of a Chiral Conglomerate with Heterotactic Helical Coordination Arrays

Helix represents the most essential molecular chiral symmetry at a supramolecular level. Here, a unique quasiracemate conglomerate {[Cd­(L)­I­(H₂O)₃]­[Cd­(HL)­I₂(H₂O)₂]­(H₂O)₄}_<i>n</i> (<b>1</b>, HL = <i>N</i>-(3,5-di­(pyridin-3-yl)-4<i>H</i>-1,2,4-triazol-4-yl)­nicotinamide), which crystallizes in <i>P</i>2₁ space group and consists of two different sets of helical enantiomers, has been successfully constructed. Remarkably, crystal transformations from the chiral quasiracemate <b>1</b> to two different achiral racemates {[Cd­(L)­I­(H₂O)₃]·(H₂O)₃}_<i>n</i> (<b>2</b>) and {[Cd­(HL)­I₂(H₂O)₂]­(H₂O)}_<i>n</i> (<b>3</b>) can be achieved controllably by introducing acid and base additives, via solvent-mediated crystal transformations

Interaction between Poly(vinyl alcohol) and Layered Double Hydroxide (LDH) Particles with Different Topological Shape and Their Application in Electrospinning

To explore the influence of filler topological shape on the rheological behavior of poly­(vinyl alcohol) (PVA) aqueous solution, three kinds (nanosized layered crystals, microsized layered crystals, and nanoscrolls) of layered double hydroxides (LDHs) were synthesized. Except for nanosized layered crystals, both LDH microsized layered crystals and nanoscrolls filled system showed distinct “N” shape viscosity curves with increasing LDH loadings. Notably, the one-dimensional LDH nanoscrolls could increase or decrease the viscosity of PVA solution by only changing the loadings. With combined theoretical calculation with dynamic mechanical analyses, the adsorbed state of PVA chains on surface of the three LDH particles was proposed, in which PVA chains exhibited various adsorbed states due to different interactions between PVA chains and LDH particles with disparate topological shape. Taking the advantage of remarkable rheological modulation and adsorption capacity, LDH nanoscrolls were introduced into PVA aqueous solution to broaden effectively its electrospinnable concentration window from 8.5–11.3 wt % to 6.5–18.0 wt %. More importantly, the adsorption capacity of LDH nanoscrolls was well preserved in the as-electrospun composite nanofibers, implying a superior adsorbent for methyl orange from wastewater was obtained

Coordination Assembly of Zn^II/Cd^II Terephthalate with Bis-Pyridinecarboxamide Tectons: Establishing Net Entanglements from [3 + 3] Interpenetration to High-Connected Self-Penetration

Four polymeric d¹⁰ metal terephthalate complexes incorporating bis-pyridinecarboxamide building blocks were prepared to explore the effect of the central metal ion or the fluorine substituent of the ligand on the topology and entanglement of coordination networks. The combination of Zn^II terephthalate with a fluorinated ligand leads to a noninterpenetrated coordination layer with honeycomb (hcb) topology for complex <b>1</b>. Interestingly, the other three materials display the unusual entangling coordination networks. For <b>2</b>, the reaction of zinc terephthalate with nonfluorinated ligand affords three-dimensional diamond (dia) architecture of [3 + 3] interpenetration, while the Cd^II terephthalate complexes <b>3</b> and <b>4</b> with the two types of bis-pyridinecarboxamide tectons show the isostructural self-penetrating framework with unique 8-connected (4¹⁷.6¹¹) topology