Inexpensive and robust iron-based electrode substrates for water electrolysis and energy storage

The instability of iron under anodic conditions makes iron-based electrode substrates unsuitable for alkaline electrolyzers and rechargeable alkaline batteries. Therefore, significantly more expensive substrates such as nickel foam or sintered nickel are used. Nickel adds a significant cost to electrolysis and energy storage systems. We show that iron substrates can be stabilized using a unique protective thermal coating. These coatings can also yield some of the most electrocatalytically active electrodes in addition to showing no notable change in performance even after 1500 h of anodic polarization. Besides sintered iron, low-carbon steel mesh can be stabilized similarly. Low-carbon steel protected by a thin layer of lithium-doped cobalt spinel was found to be an excellent current collector for positive nickel hydroxide electrodes in alkaline batteries. Thus, surface-modified iron substrates, 40 times less expensive than nickel, are promising for lowering the material costs of alkaline water electrolyzers and rechargeable alkaline batteries.     

Engineering of superhydrophobic silica microparticles and thin coatings on polymeric films by ultrasound irradiation

Superhydrophobic coatings are one of the recent hot topics in industrial applications as well as academic studies. The mimicking lotus leaves' superhydrophobic properties have been successfully transferred to real-life applications. However, the current preparation methods used to obtain superhydrophobic coatings are still complex, commonly are not transparent and/or not durable.In the present study, a new relatively simple way to prepare superhydrophobic coatings on polymeric films is described. First, superhydrophobic silica microparticles (MPs) were synthesized by fluorination of SiO₂ MPs produced by a modified Stöber method. Briefly, tetraethyl orthosilicate was polymerized in an ethanol/water continuous phase under basic conditions, and the resultant SiO₂ MPs were dispersed in heptane as a continuous phase and reacted with 1H,1H,2H,2H-perfluorododecyltrichlorosilane (FTS) to yield FTS-SiO₂ MPs, which were dried and dispersed in decane. Superhydrophobic thin coatings were then produced by a ‘throwing stones’ sonication technique and deposited onto polycarbonate, polypropylene, polyethylene, and polyurethane films. The coatings are durable, may be transparent, and exhibit self-cleaning properties for the specific practical applications. The MPs and coated polymeric films were characterized by dynamic light scattering, high-resolution scanning electron microscopy, water contact and sliding angle measurements, and infrared and x-ray photoelectron spectroscopy. This ultrasound-assisted coating process may be upscaled and applied to many polymeric films, for instance polymethyl methacrylate, polystyrene, and polyvinyl chloride. Various applications are envisaged, including but not limited to self-cleaning windows, anti-sticking of snow to antennas and windows, solar panels, roof tiles, agricultural applications, corrosion resistance, and anti-biofouling.     

Selective and Sensitive Determination of Paracetamol and Levodopa with Using Electropolymerized 3,5-Diamino-1,2,4-triazole Film on Glassy Carbon Electrode

For determination of levodopa (L-DOPA) and paracetamol (PAR), selective, effective and sensitive electrochemical sensor based on 3,5-diamino-1,2,4-triazole (35DT) on glassy carbon (GC) electrode was reported. The DPV method was used to obtain the oxidation peak current of L-DOPA which increased linearly with its concentration at the range of 1–99 μM and 99–480 μM. The linear relationship between the concentration of PAR and its peak current was obtained in the range of 0.3–55 μM and 55–475 μM. The limit of detection values for PAR and L-DOPA were found to be 0.1 and 0.25 μM, respectively. Satisfactory results were obtained in pharmaceutical samples.     

Nitrogen-Doped Carbon-Coating Disproportionated SiO Materials as Long Cycling Stable Anode for Lithium Ion Batteries

Silicon monoxide (SiO) is a kind of promising anode material for lithium-ion batteries because of its smaller volume change during the charge and discharge process than pure silicon and its higher theoretical capacity than commercialized graphite. However, its fast-fading capacity still restricts the development of practical application of SiO. A simple and cheap strategy to dope nitrogen and coat carbon on the surface of disproportionated SiO is proposed to improve the cycling stability significantly even at a high specific current. The capacity retention is nearly 85% after 250 cycles and more than 69% after 500 cycles at a specific current of 1000 mA g⁻¹. Even at a specific current of 2000 mA g⁻¹, its cycling performance behaves similarly to that of 1000 mA g⁻¹. Nitrogen doping in materials could improve the conductivity of materials because pyridinic nitrogen and pyrrolic nitrogen could improve the electron conductivity and provide defects to contribute to the diffusion of lithium ions. The use of pitch and melamine, which are easily available industrial raw materials, makes it possible to contribute to the practical application.     

IR Reflective LaPO4 Ceramic Colorant Reinforced Polymer Composite Coatings on Glass and Metal Substrates for Heat Management Applications

LaPO₄ ceramic colorants were processed in the vibrant shades of green and brick red, and subsequently embedded in polymer resins for the fabrication of heat management coatings. The IR/UV shielding characteristics of these ceramic colorants and polymer coatings were analysed and it was found that the ceramic dispersoids enhance the IR reflectance quality of polymer resins by 20 to 25 times. The nano ceramic green colorant-reinforced polymer coating on glass panels offers the stringent property, i. e., optical transparency and heat reflectance combined, when exposed to direct sunlight. Other photophysical properties were also studied and analysed. The brick red colorant entrenched resin coating on metal substrate offered heat reflectance and corrosion resistance characteristics. XPS studies provided the chemical environment of the systems. Surface morphology, crystallinity and particle size of the products were investigated using SEM, TEM, XRD and DLS techniques. The polymer resin coating of these ceramic colorants offers thermal stability and colorfastness properties.     

Enhanced contact properties of spray-coated AgNWs source and drain electrodes in oxide thin-film transistors

Facile patterning of electrodes is required for various electronic applications, particularly in solution-processed oxide thin-film transistors (TFTs). In this study, source and drain electrodes were prepared from silver nanowires (AgNWs) using spray-coating and hot press techniques. Although spray coating allowed production of AgNW patterns, which could function as electrodes in oxide TFT, the as-sprayed films did not provide a sufficient physical contact with oxide semiconductors and formed interspaces that impeded electron injection. At the same time, hot press technique produced denser AgNW networks that had a tight contact with the oxide semiconductors. As a result, hot-pressed films were considered as satisfactory source and drain electrodes for high-performance oxide TFTs, as they provided an easy electron injection. Finally, the prepared oxide TFTs with hot-pressed AgNW electrodes exhibited average field-effect mobility of 4.75 ± 1.5 cm²/V, significantly higher than that of the TFTs with as-sprayed AgNW electrodes (0.08 ± 0.05 cm²/V).     

Sonochemical coating of Prussian Blue for the production of smart bacterial-sensing hospital textiles

In healthcare facilities, environmental microbes are responsible for numerous infections leading to patient’s health complications and even death. The detection of the pathogens present on contaminated surfaces is crucial, although not always possible with current microbial detection technologies requiring sample collection and transfer to the laboratory. Based on a simple sonochemical coating process, smart hospital fabrics with the capacity to detect live bacteria by a simple change of colour are presented here. Prussian Blue nanoparticles (PB-NPs) are sonochemically coated on polyester-cotton textiles in a single-step requiring 15 min. The presence of PB-NPs confers the textile with an intensive blue colour and with bacterial-sensing capacity. Live bacteria in the textile metabolize PB-NPs and reduce them to colourless Prussian White (PW), enabling in situ detection of bacterial presence in less than 6 h with the bare eye (complete colour change requires 40 h). The smart textile is sensitive to both Gram-positive and Gram-negative bacteria, responsible for most nosocomial infections. The redox reaction is completely reversible and the textile recovers its initial blue colour by re-oxidation with environmental oxygen, enabling its re-use. Due to its simplicity and versatility, the current technology can be employed in different types of materials for control and prevention of microbial infections in hospitals, industries, schools and at home.     

用于人类脂肪干细胞的纯化和体外长期培养的聚合物涂层

采用紫外固化法制备了基于丙烯酸酯类水凝胶的聚合物涂层(PC),并用X射线光电子能谱(XPS)、水接触角(WCA)和原子力显微镜(AFM)分别对PC进行了化学组成和表面性能的表征.在PC表面进行了人类脂肪干细胞(h ASC)的体外长期培养扩增,得到的第3代细胞的生物学表征结果表明,干细胞在PC表面能正常黏附生长,流式细胞仪检测发现干细胞对特征标记物CD49d,CD73,CD105的阳性显性比例较高,对HLA-DR和CD31几乎不显性,说明扩增的干细胞具有h ASC特征.对PC上扩增的干细胞进行诱导分化,并用油红O、茜素红和阿利新蓝分别进行染色分析,结果表明,该干细胞保留了h ASC的多能特性:能分化为成脂、成骨和成软骨细胞.含有单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)、甲基丙烯酸环己酯(CHMA)和甲基丙烯酸-2-(二乙氨基)乙酯(DEAEMA)的PC2(质量比为3∶1∶2)在用于h ASC体外长期培养时,比其它PC和TCP更有利于细胞的黏附和增殖,纯化细胞,保持其多能性.实时荧光定量PCR(RT-q PCR)的分析表明PC2上得到的细胞更容易向成骨和成软骨细胞分化.     

Surface/interface phenomena in nano‐multilayer coating under severing tribological conditions

An extensive study of surface/interface phenomena during wear of an adaptive TiAlCrSiYN/TiAlCrN nano‐multilayer coating deposited using physical vapor deposition was undertaken under increasingly severe tribological conditions associated with dry end milling of H13 hardened tool steel. The results of FEM modeling on the temperature/stress distribution at different cutting speeds outline actual cutting conditions on the both rake and flank frictional surfaces of the coated tool. Studies of the surface/interface phenomena were made by means of SEM/high‐resolution transmission electron microscopy/XPS analyses. Results demonstrate that intensifying tribological conditions facilitates improved wear performance of the adaptive coating layer. In extreme tribological conditions of ultra‐performance machining (cutting speed of 500 m/min), the self‐organization process establishes entirely through the formation of a nano‐scale layer of dynamically re‐generating tribo‐ceramic films. The formation of these surface nano‐films results in exceptionally efficient protection of the underlying coating layers. In response to the extreme external environment, the coating layer remained almost undamaged during a long run, demonstrating the capacity to efficiently replenish necessary tribo‐ceramic films. In this way, interconnection of various surface and undersurface processes is established in the hierarchically structured tribo‐films/coating layer. This integral performance is responsible for exceptional wear resistance under intensifying and extreme tribological conditions. Copyright © 2016 John Wiley & Sons, Ltd.