Robust and durable liquid-repellent surfaces.

Liquid-repellent surfaces, such as superhydrophobic surfaces, superoleophobic surfaces, and slippery liquid-infused surfaces, have drawn keen research interest from the communities engaged in chemical synthesis, interfacial chemistry, surface engineering, bionic manufacturing and micro-nano machining. This is due to their great potential applications in liquid-proofing, self-cleaning, chemical resistance, anti-icing, water/oil remediation, biomedicine, etc. However, poor robustness and durability that notably hinders the real-world applications of such surfaces remains their Achilles heel. The past few years have witnessed rapidly increasing publications that address the robustness and durability of liquid-repellent surfaces, and many breakthroughs have been achieved. This review provides an overview of the recent progress made towards robust and durable liquid-repellent surfaces. First, we discuss the wetting of solid surface and its generally-adopted characterisation methods, and introduce typical liquid-repellent surfaces. Second, we focus on various evaluation methods of the robustness and durability of liquid-repellent surfaces. Third, the recent advances in design and fabrication of robust and durable liquid-repellent surfaces are reviewed in detail. Fourth, we present the applications where these surfaces have been employed in fields like chemistry, engineering, biology and in daily life. Finally, we discuss the possible research perspectives in robust and durable liquid-repellent surfaces. By presenting such state-of-the-art of this significant and fast-developing area, we believe that this review will inspire multidisciplinary scientific communities and industrial circles to develop novel liquid-repellent surfaces that can meet the requirements of various real-world applications.

Preparation of Fe-HMOR with a Preferential Iron Location in the 12-MR Channels for Dimethyl Ether Carbonylation.

As the Brønsted acid sites in the 8-membered ring (8-MR) of mordenite (MOR) are reported to be the active center for dimethyl ether (DME) carbonylation reaction, it is of great importance to selectively increase the Brønsted acid amount in the 8-MR. Herein, a series of Fe-HMOR was prepared through one-pot hydrothermal synthesis by adding the EDTA-Fe complex into the gel. By combining XRD, FTIR, UV-Vis, Raman and XPS, it was found that the Fe atoms selectively substituted for the Al atoms in the 12-MR channels because of the large size of the EDTA-Fe complex. The NH3-TPD and Py-IR results showed that with the increase in Fe addition from Fe/Si = 0 to 0.02, the Brønsted acid sites derived from Si-OH-Al in the 8-MR first increased and then decreased, with the maximum at Fe/Si = 0.01. The Fe-modified MOR with Fe/Si = 0.01 showed the highest activity in DME carbonylation, which was three times that of HMOR. The TG/DTG results indicated that the carbon deposition and heavy coke formation in the spent Fe-HMOR catalysts were inhibited due to Fe addition. This work provides a practical way to design a catalyst with enhanced catalytic performance.

Phase coupling of acoustic and optical modes in antiferromagnetic materials CrCl3.

In layered antiferromagnetic material CrCl3, due to the antiferromagnetic coupling between two magnetic sublattices, there are two antiferromagnetic resonance modes, called acoustic mode with in-phase precession and optical mode with out-of-phase precession. By using Landau-Lifshitz-Gilbert equation, we study the magnetization dynamics of the two sublattices in CrCl3. A coupling resonance mode appears at the coupling point when the acoustic and optical magnon modes are tuned by an applied magnetic field, which is called 'coupling mode'. In this paper, we present an explanation for the coupling of the acoustic and the optical mode. Our calculation shows that the coupling of the acoustic and optical mode is accomplished by change of the precession phase-difference between two magnetic sublattices.

Highly transparent graphene oxide/cellulose composite film bearing ultraviolet shielding property.

This work investigates the ultraviolet (UV) shielding property of composite films synthesized with graphene oxide (GO) nanosheets and regenerated cellulose. Regenerated cellulose was prepared from ZnCl2/CaCl2/GO solution. The GO sheets presented a homogenous dispersion in the film matrix. The incorporation of GO endows the cellulose films with improved UV shielding capacity. When GO loading reaches 2%, the UVA and UVB blocking percentages are 66.7% and 54.2%, respectively. Moreover, the composite films had excellent visible light transmittance. The resulting films possess promising applications as protective and packing materials.

Zirconium ion modified melamine sponge for oil and organic solvent cleanup.

Hydrophilic melamine sponge is transferred into hydrophobic melamine sponge by immersing the commercial melamine sponge cubes into zirconium oxychloride aqueous solution and followed by a simple dry process. The hydrophobicity transformation is assigned to the complex bonds constructed by the Zr4+ ions and N atoms, thus reducing the surface polarity. The modified melamine sponge presents excellent absorption capacities toward various oils and organic solvents (70-181 g/g). Its contact angle with water can reach 130° or more, and displays good oil-water selectivity for both heavy oil and light oil. Besides, the sponge has stable chemical properties and good recyclability. This work presents a facile and low-cost method for fabrication of hydrophobic materials that might be used for the cleanup of oil spills.

Species-level evaluation of the human respiratory microbiome.

BACKGROUND: Changes to human respiratory tract microbiome may contribute significantly to the progression of respiratory diseases. However, there are few studies examining the relative abundance of microbial communities at the species level along the human respiratory tract. FINDINGS: Bronchoalveolar lavage, throat swab, mouth rinse, and nasal swab samples were collected from 5 participants. Bacterial ribosomal operons were sequenced using the Oxford Nanopore MinION to determine the relative abundance of bacterial species in 4 compartments along the respiratory tract. More than 1.8 million raw operon reads were obtained from the participants with ∼600,000 rRNA reads passing quality assurance/quality control (70-95% identify; >1,200 bp alignment) by Discontiguous MegaBLAST against the EZ BioCloud 16S rRNA gene database. Nearly 3,600 bacterial species were detected overall (>750 bacterial species within the 5 dominant phyla: Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes, and Fusobacteria. The relative abundance of bacterial species along the respiratory tract indicated that most microbes (95%) were being passively transported from outside into the lung. However, a small percentage (<5%) of bacterial species were at higher abundance within the lavage samples. The most abundant lung-enriched bacterial species were Veillonella dispar and Veillonella atypica while the most abundant mouth-associated bacterial species were Streptococcus infantis and Streptococcus mitis. CONCLUSIONS: Most bacteria detected in lower respiratory samples do not seem to colonize the lung. However, >100 bacterial species were found to be enriched in bronchoalveolar lavage samples (compared to mouth/nose) and may play a substantial role in lung health.

Metal nanoparticle-embedded bacterial cellulose aerogels via swelling-induced adsorption for nitrophenol reduction.

Bacterial cellulose aerogels were chosen as the substrate for supporting and dispersing metal nanoparticles (Cu and Ni). During the catalyst preparation, we found that the swelling-induced adsorption process could control the metal size and dispersion simultaneously. Cu and Ni nanoparticles were confined into the bacterial cellulose network and SEM results demonstrated that Cu particles had a smaller size compared to Ni particles. The metal-loaded catalysts exhibited good catalytic performance in the 4-nitrophenol reduction reaction. The optimal sample (BC-Cu-0.5) prepared with 0.5 wt% CuSO4 solution could complete the reduction process within 8 min. Besides, the BC-Cu-0.5 catalyst showed excellent stability and reusability. This study sheds light on the deposition of metal particles and provides a wider application for bacterial cellulose.

Construction of hydrophobic alginate-based foams induced by zirconium ions for oil and organic solvent cleanup.

Hydrophobic modification of sodium alginate (SA) foams via a simple freeze-drying and post cross-linking induced by zirconium (Zr) ions was developed. All results demonstrated that Zr ions not only constructed surface microstructure but also lowered surface energy of foams, leading to the hydrophobic character. Hydrophobic and oleophilic foams showed excellent adsorption capacities for different oils and organic solvents (11.2-25.9 g/g). Furthermore, SA solution can be also coated on porous substrates, such as melamine sponges (MS) and Nylon strainers (NS), to give hydrophobic modification by Zr ion crosslinking. These excellent performances made them a promising for oil adsorption and cleanup.

A green strategy for preparing durable underwater superoleophobic calcium alginate hydrogel coated-meshes for oil/water separation.

Superhydrophilic and underwater superoleophobic calcium alginate (CA) hydrogel-coated meshes (CAHMs) were prepared via a green dip-coating and self-assembly method without adding any toxic or expensive modifying agents. Since meshes possess intrinsic chemical inert characterisitics, the first CA layer was employed as a precoating and then continually facilitated deposition of CA hydrogel via coordination bonding to form extraordinary underwater superoleophobicity. All results proved that CA was introduced to generate both hydrophilic chemical compositions and rough structures onto resultant mesh surfaces. The obtained meshes, which possessed a underwater oil contact angle (UOCA) of ~154.3° and low oil sliding angle (OSA) of ~7°, could separate various oil/water mixtures with efficiency above 99% and maximum water flux up to 28,108.9 L·m-2·h-1. This separation process was spontaneous and only driven by gravity. Furthermore, as-prepared meshes still maintained high stability under corrosive organic solvents. These outstanding performances made it a promise for oil/water separation in the future.

Sustainable and scalable in-situ synthesis of hydrochar-wrapped Ti3AlC2-derived nanofibers as adsorbents to remove heavy metals.

To ensure a sustainable future, it is imperative to efficiently utilize abundant biomass to produce such as platform chemicals, transport fuels, and other raw materials; hydrochar is one of the promising candidates derived by hydrothermal carbonization of biomass in pressurized hot water. The synthesis of "hydrochar-wrapped Ti3AlC2-derived nanofibers" was successfully achieved by a facile one-pot hydrothermal reaction using glucose as the hydrochar precursor. Meanwhile, cellulose and pinewood sawdust as raw materials were also investigated. Products were characterized by XRD, N2 adsorption-desorption isotherms, SEM, TEM and FT-IR to investigate their crystal structures, textural properties, morphologies, and surface species. In the adsorption test to remove Cd(II) and Cu(II) in aqueous solution, hydrochar-wrapped nanofibers outperformed pure nanofibers derived from Ti3AlC2, hydrothermal carbon derived from glucose and commercial activated carbon. Finally, the regeneration, sorption kinetics, and possible adsorption mechanism were also explored.

Alginate-based attapulgite foams as efficient and recyclable adsorbents for the removal of heavy metals.

Floatable and porous foam adsorbents constructed by encapsulating attapulgite (ATP) in sodium alginate (SA) were fabricated via a freeze-drying and post cross-linking method, and both attapulgite and sodium alginate possessed adsorptive sites. These adsorbents were characterized by XRD, FTIR, and SEM to investigate their crystal structures, surface properties, size and morphology. In the adsorption tests, the adsorption capacity was derived from the Langmuir isotherm model, and the maximal adsorption capacity of as-prepared adsorbents was 119.0 mg g-1 for Cu(II) and 160.0 mg g-1 for Cd(II). In addition to the remarkable adsorptive performances, these adsorbents presented strong chemical stability and were readily recyclable because of their floatability in water solution. These aforementioned advantages highlight that the alginate-encapsulated attapulgite foams are potential scalable adsorbents for heavy metal ions removal from polluted water, and such a structure design could intrigue the development of novel adsorptive materials.

In-situ gelation of sodium alginate supported on melamine sponge for efficient removal of copper ions.

Sodium alginate-melamine sponge composites were fabricated by in-situ gelation of sodium alginate supported on the commercial melamine sponge (MS). MS serves as the three-dimensional skeleton for alginate coating and can effectively avoid the shrink of alginate, and thus makes the alginate-MS composites user-friendly and facile to recover. In the adsorption test, the adsorption process is pseudo-second order and matches the Langmuir model with the maximum adsorption capacity of 90.1mg/g for copper ions. The alginate-MS is recyclable and presents enhanced mechanical properties compared with those of pristine MS. All these properties make such alginate-MS a promising candidate as an adsorbent for heavy metal removal.

Simple fabrication of easy handling millimeter-sized porous attapulgite/polymer beads for heavy metal removal.

A simple method was offered to synthesize porous attapulgite (ATP)/polymer beads. The polymeric network acts as both holder to support ATP inside the inner pore structure and as the obstacle to avoid the agglomeration of ATP during the adsorption process. Moreover, such beads are millimeter-size and can float on water surface, making such beads easy-to-handle and facile-to-recover without weight loss. The maximum adsorption capacity of such beads for Cu(II) and Cd(II) were 25.3 and 32.7mg/g, respectively, and pH value plays a key role in determining the adsorption capacities. The ATP/polymer beads also show good recycling ability and chemical stability. All these properties make such beads promising candidates as adsorbents for heavy metal removal.

Nanoscale Ni-B electrocatalyst prepared from nickel ethylenediamine complex for direct ethanol electrocatalytic oxidation.

Ni-B/Cu electrode prepared by the electroless deposition technique of chemical reduction of nickel ethylenediamine complex with BH4- was characterized by SEM, XRD and XPS techniques, respectively, and evaluated using ethanol electrocatalytic oxidation by the method of cyclic voltammetry. The as-prepared Ni-B/Cu electrode exhibited much higher electrocatalytic activity than the Ni-B/Cu electrode obtained via direct reduction of nickel metallic ions. The effects of the nickel ethylenediamine complex can be attributed to both the structural effect and electronic effect. The nickel ethylenediamine complex can not only make an electroless deposition stable and highly dispersed, but also facilitate the formation of more nanoscale microcrystalline Ni on the electrode surface, which increased the electrochemical oxidation activity. Moreover, ethylenediamine influenced the electronic states of Ni and B on the electrode surface, more electrons transfer from the B to Ni that the Ni active sites became more highly unsaturated, which could promote the form of adsorbed active ethanol.

Meso-macro-porous monolithic Pt-Ni/Al(2)O(3) catalysts used for miniaturizing preferential carbon monoxide oxidation reactor.

Meso-macro-porous monolithic Pt-Ni/Al(2)O(3) catalysts with platinum and nickel in interaction and in a highly dispersed state have been successfully prepared, and the obtained catalysts are highly efficient for CO removal from hydrogen rich gases via preferential oxidation; the results show that preparing catalysts to meso-macro-porous monolithic structure is a promising way for the miniaturization of CO removing reactor.

Improvement of the functions of osteoblasts seeded on modified poly(D,L-lactic acid) with poly(aspartic acid).

One of the challenges in the field of tissue engineering is the development of biomaterial/cell interactions. For the purposes of the present study, two molecular weights of poly(aspartic acid) (PASP) were used to modify poly(D,L-lactic acid) (PDLLA) films in order to enhance their cell affinity. The properties of the PDLLA-modified surfaces and the controls were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). These data reflect the change in the biocompatibility of modified PDLLA surfaces. Then rat osteoblasts were seeded onto these modified surfaces and on controls to examine their effects on cell adhesion and proliferation. Cell morphologies on these surfaces were studied by scanning electron microscopy (SEM), and cell viability was evaluated with a MTT assay. In addition, differentiated cell function was assessed by measuring alkaline phosphatase (ALP) activity. The results suggest that PASP-modified surfaces may enhance the interactions between osteoblasts and PDLLA films.