Nanostructured Components Research Articles

Dispersant Molecules with Functional Catechol Groups for Supercapacitor Fabrication.

Cathodes for supercapacitors with enhanced capacitive performance are prepared using MnO2 as a charge storage material and carbon nanotubes (CNT) as conductive additives. The enhanced capacitive properties are linked to the beneficial effects of catecholate molecules, such as chlorogenic acid and 3,4,5-trihydroxybenzamide, which are used as co-dispersants for MnO2 and CNT. The dispersant interactions with MnO2 and CNT are discussed in relation to the chemical structures of the dispersant molecules and their biomimetic adsorption mechanisms. The dispersant adsorption is a key factor for efficient co-dispersion in ethanol, which facilitated enhanced mixing of the nanostructured components and allowed for improved utilization of charge storage properties of the electrode materials with high active mass of 40 mg cm−2. Structural peculiarities of the dispersant molecules are discussed, which facilitate dispersion and charging. Capacitive properties are analyzed using cyclic voltammetry, chronopotentiometry and impedance spectroscopy. A capacitance of 6.5 F cm−2 is achieved at a low electrical resistance. The advanced capacitive properties of the electrodes are linked to the microstructures of the electrodes prepared in the presence of the dispersants.

Mechanical Properties of DNA Hydrogels: Towards Highly Programmable Biomaterials

DNA hydrogels are self-assembled biomaterials that rely on Watson–Crick base pairing to form large-scale programmable three-dimensional networks of nanostructured DNA components. The unique mechanical and biochemical properties of DNA, along with its biocompatibility, make it a suitable material for the assembly of hydrogels with controllable mechanical properties and composition that could be used in several biomedical applications, including the design of novel multifunctional biomaterials. Numerous studies that have recently emerged, demonstrate the assembly of functional DNA hydrogels that are responsive to stimuli such as pH, light, temperature, biomolecules, and programmable strand-displacement reaction cascades. Recent studies have investigated the role of different factors such as linker flexibility, functionality, and chemical crosslinking on the macroscale mechanical properties of DNA hydrogels. In this review, we present the existing data and methods regarding the mechanical design of pure DNA hydrogels and hybrid DNA hydrogels, and their use as hydrogels for cell culture. The aim of this review is to facilitate further study and development of DNA hydrogels towards utilizing their full potential as multifeatured and highly programmable biomaterials with controlled mechanical properties.

Development of a porous iron-based magnetic absorber with enhanced electromagnetic absorption performance

It is well known that the electromagnetic (EM) wave absorption performance is determined by nanostructure and material components. Based on this principle, this study reports a facile two-step method for synthesizing porous Fe/α-Fe2O3 nanoparticles with a tunable component ratio. The as-prepared hybrids, especially their pore size and phase composition, were characterized by X-ray diffraction (XRD), BET, and X-ray photoelectron spectroscopy (XPS). Furthermore, the EM wave performance was estimated by the coaxial line method, which revealed that a thin layer of nanoparticles (≤ 1.5 mm) exhibited good performance. The desirable bandwidth (reflection loss, RL ≤ − 10 dB) of 5.2 GHz was obtained when the thickness was 1.2 mm. The bandwidth was greater than 2.0 GHz when the thickness was 1.0 mm. The EM wave loss mechanism, especially the contribution of a porous structure, is discussed in depth. In addition, a suitable weight ratio is essential to balance impedance matching and attenuation ability.

Phase-Controlled 1T Transition-Metal Dichalcogenide-Based Multidimensional Hybrid Nanostructures

Phase-Controlled 1T Transition-Metal Dichalcogenide-Based Multidimensional Hybrid Nanostructures

Investigation of Physical and Mechanical Properties of Rubbers Reinforced by Carbon Nanostructured Components

The work presents investigation results of physical and mechanical properties of rubber mixtures based on SKI-3 and SKS-30-ARKM-15 rubbers reinforced with hybrid filler carbon black/carbon nanotubes (CB/CNT). Elasticity, hardness and strength were measured according to standard procedures presented in GOST. The content of the carbon nanotubes in rubber mixtures was 0,5 wt. %. parts per 100 wt. parts of rubber. According to experiments, it was found that the introduction of CB/CNT masterbatches into the structure of both investigated rubbers reduces their elasticity and increases Shore A hardness. During uniaxial tension of the tested rubbers, it was found that the presence of the nanostructured CB/CNT filler in the rubber structure leads to an increase in the nominal strength for SKI-3-based rubber by 19,6 %, and on SKS-30-ARKM-15 by 22,5 %. Therefore, the use of CB/CNT nanostructures as a rubber filler is a promising method of improving rubber performance characteristics.

Research of new materials and approaches in additive technologies in the manufacture of prototypes in industrial design

In industrial design, in the manufacture of the prototype, the task of choosing the technology and material for its manufacture is taken. At the minimum cost of material, it is necessary to obtain a prototype with high strength indicators, which will guarantee the implementation of the tasks for which the prototype was conceived. The use of additive technologies allows you to get prototypes with a cellular internal structure, which can significantly save the expendable material when prototyping the future product. In this paper, we analyze the approaches that contribute to improving the strength characteristics of a prototype made using additive technology, and also show the promise of research in the direction of finding the shape of cells with the greatest strength. As a hypothesis, it has been suggested that an increase in the strength characteristics of the prototype can be achieved by introducing nanostructured materials into the polymer. Studies were conducted on the synthesis of nanostructured materials in low-temperature plasma and their modification of polylactide. Samples were made from modified polylactide and their strength characteristics were investigated. An analysis of the results showed an increase in the strength characteristics of samples of modified polylactidapo compared with samples made of primary polylactide without nanostructured components.

Multicomponent Co9S8@MoS2 nanohybrids as a novel trifunctional electrocatalyst for efficient methanol electrooxidation and overall water splitting

In view of the importance of multifunctional catalysts that can drive different electrocatalytic reactions in the same electrolyte solution, we designed and prepared a series of multicomponent nanohybrids composed of Co9S8 and MoS2 derived from cobalt-doped polyoxometalate (Co-POMs) by one-pot calcination method. The obtained Co9S8@MoS2 nanohybrids were composed of Co9S8, MoS2, Co-Mo-S phases and assembled nanosheets, and therefore were explored as trifunctional electrocatalysts for hydrogen evolution reaction, oxygen evolution reaction, and methanol oxidation reaction (MOR) in an alkaline medium. The nanostructure and chemical components of the series of Co9S8@MoS2 nanohybrids can be modulated by changing the mole ratios of H5Mo12O41P to Co(NO3)2 precursor. Compared with the sole component and other reported Co9S8@MoS2 nanohybrids, the Co9S8@MoS2 nanohybrid prepared from the 1:1 ratio of PMo12 and Co(NO3)2 exhibited superior MOR catalysis efficiency (121.4 mA cm−2) and an extremely low overpotential (1.49 V) for overall water splitting at a current density of 10 mA cm−2 owning to the effective synergism among Co9S8, MoS2, and Co-Mo-S phase. Overall, this study provides a feasible approach to developing efficient and stable trifunctional bimetal electrocatalysts for clean-energy applications.

MoTe2 as a natural hyperbolic material across the visible and the ultraviolet region

Hyperbolic materials are of particular interest for the next generation of photonic and optoelectronic devices. Since artificial metamaterials are intrinsically limited by the size of their nanostructured components, there has been a hunt for natural hyperbolic materials in the last few years. In a first-principles work based on density-functional theory and many-body perturbation theory, we investigate the fundamental dielectric response of MoTe2 in monolayer, bilayer, and bulk form, and find that it is a natural type-II hyperbolic material with low losses between 3 and 6 eV. Going from the monolayer to the bulk, the energy window of hyperbolic dispersion is blue-shifted by a few tenths of an eV. We show that excitonic effects and optical anisotropy play a major role in the hyperbolic behavior of MoTe2. Our results confirm the potential of layered materials as hyperbolic media for opto-electronics, photonics, and nano-imaging applications.

WITHDRAWN: Beef tenderness evaluation using early post-mortem muscle nanostructure.

Ahead of Print article withdrawn by publisher.

Ferroelectric control of magnetic skyrmions in multiferroic heterostructures

Magnetic skyrmions with a topological particle nature are considered as potential information carriers for future spintronics memory and logic devices. The stabilization of magnetic skyrmions at zero magnetic field in nanostructured components is a prerequisite for incorporating them into advanced nonvolatile memory devices. Here, using a real-space phase field model based on Ginzburg-Landau theory, we demonstrate that ferroelectric polarization can stabilize magnetic skyrmions at zero magnetic field in multiferroic heterostructures composed of MnSi, ${\mathrm{PbTiO}}_{3}$, and ${\mathrm{SrTiO}}_{3}$. The stabilization of magnetic skyrmions in multiferroic heterostructures essentially depends on the directions of spontaneous polarizations and the size ratios of different constituents, in which polarization-induced inhomogeneous strain plays an important role. By applying an electric field, the polarization switching takes place in the ferroelectric constituent and the polarization-induced strain changes in the multiferroic heterostructures, resulting in a transition from skyrmion to helical phase in the ferromagnetic constituent. In addition, the skyrmion and helical phases can coexist in the absence of an external field and be switched reversibly by a local magnetic field with a small magnitude. Stabilization and control of magnetic skyrmions by spontaneous polarization at zero magnetic field may create additional opportunities for nonvolatile skyrmion memory devices.

Fabrication visible-blind ultraviolet photodetector based on ZnS/GaN heterostructure with fast response

In this paper, visible-blind ultraviolet (UV) detectors based on a ZnS/p-GaN heterojunction structure were fabricated. The heterojunction structure was composed of a ZnS nanostructure deposited on a p-GaN/sapphire substrate. The ZnS nanostructured component was obtained via radio-frequency magnetron sputtering. The device based on this ZnS/p-GaN heterojunction structure showed a reproducible, stable, and fast response speed. Therefore, the results demonstrated that the ZnS/p-GaN heterojunction was successfully fabricated using this relatively low-cost method.

Experimental and numerical investigation of heat enhancement using a hybrid nanofluid of copper oxide/alumina nanoparticles in water

The following work experimentally and numerically investigated the thermal performance of a hybrid nanofluid, prepared by decorating a nanostructured aluminum oxide support with copper oxide nanostructures, in a flow system of porous open-cell foam metals. The porous medium was comprised of 6061-T6 aluminum with a porosity of 0.91 and a permeability of 9.54788 × 10−7 m2. Experiments were performed under variable heat flux, using a hybrid nanofluid consisting of a 0.1 mass% aqueous solution of CuO@Al2O3 nanocomposite particles 28 ± 11 nm in size. Thermal performance was evaluated with respect to the Nusselt number and the index of performance with pressure. Remarkably, the implementation of a copper oxide/alumina nanocomposite with the use of porously filled channels resulted in significant thermal enhancement (6–11%) relative to commercial alumina nanofluid, despite a total copper concentration of only 0.0001 mass% in the hybrid nanofluid. Increased performance is attributed to a combination of ultralow copper content and the approach to hybrid nanofluid design. Specifically, a small amount of copper significantly increased the local Nusselt number, indicative of superior heat extraction. At the same time, a numerical model of the system was also developed and agreed with experimental measurements within an error of 5%. Numerical results predicted a slightly higher pressure drop for the hybrid nanofluid, but also showed higher absolute pressures for the hybrid fluid all along the channel in the three-channel configuration. Simulation also produced an interesting discrepancy between the performances of the hybrid nanofluid as a function of heat flux, possibly related to different channel pressures inherent to the two heat sink models under investigation. This could point to a heightened pressure sensitivity of the thermal properties of hybrid nanofluids as well as a greater need to consider experimental design in the comparison of heat enhancement across nanofluidic systems. In terms of material design, decorating alumina nanoparticles with copper nanoparticles rather than mixing two individual nanostructured components appears to have been a beneficial strategy. The photochemical methodology used to prepare the nanocomposite material may also have improved thermal performance by yielding smaller (< 5 nm) copper oxide nanoparticles and provided access to the synergistic properties of a true nanocomposite material. This study demonstrates that heat enhancement by nanofluids can be achieved using a much smaller amount of copper than previously described in the literature and further highlights that synthetic methodology and material characterization can have a dramatic impact upon the performance of applied nanocomposite materials. Additionally, this work delivers a practical example of how progressive nanofunctionalization of materials can enhance thermal functionality of nanofluids.

2D and 3D orientation mapping in nanostructured metals: A review

Abstract Nanostructured metals possess various excellent properties and offer the potential for a wide range of applications. Improvements in the properties and performance of nanostructured metal components motivate a complete characterization of the microstructures and crystallographic orientations of nanostructured metals with nanoscale spatial resolution. Two well developed orientation mapping techniques for such characterization are electron backscatter diffraction (EBSD) in the scanning electron microscope and precession electron diffraction (PED) using diffraction spots in the transmission electron microscope. However, these methods can only characterize the structure in two dimensions. It is still a great challenge to characterize grains in three dimensions, i.e. from the interior of the nanostructured metals. Recently, three-dimensional orientation mapping in the transmission electron microscope (3D-OMiTEM) was developed and further improvements of this technique are introduced in this paper. Utilization of these orientation mapping techniques for structural and orientational characterizations are demonstrated by examples of surface-deformed metals with gradient nanostructures, and a sputtered gold film of nano-islands containing nanograins. The merits and challenges of each of these techniques are discussed and suggestions for further developments are proposed.

Reasons for breaking of chemical bonds of gas molecules during movement of explosion products in cracks formed in rock mass

The purpose of this study was to develop a physico-mathematical model and technique for estimation of chemical bond stability depending on electric field intensity of an external point charge. A hypothesis for a possible physico-chemical mechanism of the formation of additional harmful gases in the rock destruction by blasting was proposed. The theoretical basis of the hypothesis is the method of theretical evaluation of bond energy depending on the distance to a point charge, the third Coulomb centre. The quantum-mechanical model for calculating the electronic terms of molecules makes it possible to solve problems associated with the determination of parameters of molecules under the action of various physical fields on the system under consideration. The model was approved for some diatomic molecules. The discrepancy between the experimental data and calculated data did not exceed 14%, which proves accuracy of the obtained results. The model can be used in the field of research into the causes of gas-dynamic phenomena in underground coal mines, in studies of the degree of stability of nanostructured components of coal under physical influences, and in the theoretical design of new compounds and structures in the field of nanomaterial science and nanotechnology.

ВЛИЯНИЕ ОРГАНОМИНЕРАЛЬНЫХ СУСПЕНЗИЙ И ИХ НАНОАНАЛОГОВ НА ЭЛЕМЕНТЫ СТРУКТУРЫ УРОЖАЯ ОВСА

The article presents the results of two summer studies on the use of nanostructured suspensions of sapropel and vermicompost on gray forest medium loamy soil under the conditions of a growing experiment when growing oats of Konkur variety. We see the supply of plants with nutrients in the use of substances created by nature itself, whose chemical composition allows them to be used as fertilizers. In agriculture and crop production, various doses of sapropel and vermicompost in the soil have been studied, but there are no data on the use of their nanostructured components. For the first time in the Republic of Tatarstan, research is underway to develop ways to use sapropel and vermicompost nanomaterials in crop production when growing crops. The nature and degree of influence of macro - and nanostructured suspensions on the main elements of the crop structure during their use for pre-sowing seed treatment and foliar treatment of plants, both in a separate and in a complex application, is revealed. Presowing treatment with suspensions of vermicompost and nanobiohumus increased the height and yield of plant biomass relative to other options by 3.8 ... 26.1% and 8 ... 58.2%, respectively, in terms of structure. The complex use of treatments with nanosuspensions of sapropel and vermicompost positively affected quantitative indicators: mass of 1000 grains, roots and grains. Nanostructured suspensions possessing biologically active properties, particle sizes of 20-30 nm, penetrating unhindered, without damaging the structure and without consequences for the plant organism, stimulating biochemical processes and having a prolonged effect on biological objects, provided better crop structure indicators compared to macro-suspension treatment.

The state of cognitive functions after angioreconstructive operations on the carotid arteries

The use of nanostructured components in drug manufacturing and, more specifically, targeted drug delivery has recently become a major trend in the pharmaceutical industry. Nanodrugs encompass a wide range of pharmaceutical agents containing dendrimers, nanocrystals, micelles, liposomes, and polymer nanoparticles. Liposomes are the most well-studied nanoparticles and effective drug carriers. However, the more complex their structure is, the more process controls are needed and the more quality attributes have to be monitored, including the chemical properties of the liposomal fraction such as the shape, size and charge of the nanoparticle, conjugation efficacy, and distribution of the active ingredient. We believe that quality control of key liposome characteristics should rely on dynamic and laser light scattering coupled with electrophoresis, differential scanning calorimetry, cryo-electron microscopy, nuclear magnetic resonance, laser diffraction analysis, and gel filtration chromatography.

Dissipative Particle Dynamics Simulations of a Protein-Directed Self-Assembly of Nanoparticles.

Design and fabrication of multifunctional porous structures play key roles in the development of high-performance energy storage devices. Our experiments demonstrated that nanostructured porous components, such as electrodes and interlayers, generated from the protein-directed self-assembly of nanoparticles can significantly improve the battery performances. The protein-directed assembly of nanoparticles in solution is a complex process involving the complicated interactions among proteins, particles, and solvent molecules. In this paper, we investigate the effects of coating proteins and specific solvent environments on the assembled porous structures. Comprehensive dissipative particle dynamics (DPD) simulations have been implemented to explore the molecular interactions and uncover the fundamental mechanisms in a gelatin-directed self-assembly of carbon black particles under different solvent conditions. Our simulations show that compact triple-strand “rod-like” structures are formed in water while loose curved “sheet-like” structures are formed in an acetic acid/water mixture. The structural difference is mainly due to the redistribution of the charges on the gelatin side chains under specific acid-solvent conditions. The strong and flexible “sheet-like” structures lead to a homogenous porous structure with high porosity and with large functionalized surfaces. Our simulations results can reasonably explain the experimental observations; this work demonstrates the great potential of DPD as a powerful tool in guiding future experimental design and optimization.

Improving Wood Resistance to Decay by Nanostructured ZnO-Based Treatments

In this study, the maple wood surface was coated with nanostructured zinc oxide, grown on the surface by using a hydrothermal process, and furtherly treated with shellac varnish. Samples obtained both after ZnO treatment and after the final varnish application were characterized by different techniques, i.e., X-ray diffraction (XRD), scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDS), micro-FTIR with attenuated total reflectance (μ-ATR-FTIR), chromatic variation measurements, and contact angle determinations. Analytical results showed that the wood surface was covered by quite a homogeneous array of inorganic nanoparticles and that the natural resin forms a regular film over the ZnO nanostructures. An accelerated aging test was used to evaluate the protecting effectiveness of the treatments towards UV-induced decay of wood material. After the test, wood treated with ZnO and with the shellac/ZnO combination underwent a considerably lower chromatic change if compared to the untreated wood, suggesting an enhanced resistance of the treated maple to the decay due to light exposition. The presence of nanostructured ZnO protects from decay not only the wood substrate but also the shellac film. A microbiology test showed that growth of fungal species, e.g., common mold, is prevented on the wood surface treated with ZnO or with shellac/ZnO, indicating that the nanostructured zinc oxide also provides an effective protection from biodeterioration. The coating obtained by consecutive application of nanosized ZnO particles and shellac varnish combines the excellent aesthetical features and water repellence of the traditional finish with the protecting effectiveness of the nanostructured inorganic component.

Charge Carrier Dynamics in Metal-Oxide/Nanocarbon Hybrid Photoelectrodes

One of the most critical challenges of the 21st century is the shift in energy use from fossil fuels to renewable sources. Photoelectrochemical solar energy conversion, as a potentially attractive candidate, has gained an increased momentum during the recent years. Although both water-splitting (hydrogen evolution) and carbon dioxide reduction are promising avenues, they both have substantial shortcomings to be addressed. A common virtue of these two processes is that a good photoelectrode has to concurrently fulfill many attributes to drive these reactions efficiently. One of the most important is the efficient charge carrier transport, which ensures that most of the photogenerated charge carriers can be extracted both toward the electrode/electrolyte junction and toward the back contact. Numerous promising photoelectrode material showed poor performance due to extensive charge carrier recombination both in the bulk and at the surface. A well-known example is α-Fe2O3 (hematite), in which the hole-diffusion length is only 2-4 nm.1 One possible way to improve charge carrier transport properties is to deposit the metal-oxide on an interconnected nanocarbon network (e.g., carbon nanotubes or graphene). These highly conductive nanoscaffolds can improve the transport of the photogenerated charge carriers, which in turn, results in an enhanced photoelectrochemical performance.2 In my presentation, I am going to discuss how charge carrier dynamics of various hematite and hematite/nanocarbon composites is affected by the composition of the nanohybrids and by the applied bias. Hematite/nanocarbon photoelectrodes were synthesized by a two-step method: first the nanocarbon layer was spray-coated on the surface of the substrate electrode, and the nanostructured metal-oxide component was electrodeposited in a subsequent step. The metal-oxide/nanocarbon ratio was precisely controlled by the deposition charge density. To investigate charge carrier dynamics on a timescale ranging from seconds to femtoseconds three different techniques were employed: (i) transient absorption spectroscopy, employing a fs pump-probe setup, (ii) intensity-modulated photocurrent spectroscopy, and finally (iii) fast chronoamperometry. By covering this broad timescale, it was possible to study charge carrier transport, trapping and recombination processes, which were greatly affected by both the applied potential and the presence of the nanocarbons. 1 Energy Environ. Sci., 2016, 9, 2744—2775. 2 J. Am. Chem. Soc. 2017, 139, 6682−6692.

Nanometallurgical Silicon for Energy Application

Download : Download high-res image (136KB) Download : Download full-size image Professor Ralf B. Wehrspohn was appointed jointly by the Martin Luther University (MLU) Halle-Wittenberg and the Fraunhofer Gesellschaft to work in Halle. As the youngest institute director in the Fraunhofer Gesellschaft, he has headed the Fraunhofer Institute for Microstructure of Materials and Systems IMWS since 2006. He holds the chair of Microstructure-Based Material Design at the MLU. His main areas of work are nanostructure materials and components, such as those used in microelectronics, sensors, photonics, and photovoltaics. Download : Download high-res image (189KB) Download : Download full-size image Xiaopeng Li studied in Professor Wehrspohn’s group from 2010 to 2013. He received his doctorate degree with highest honor Summa Cum Laude. Since 2014, he has been working in Shanghai Advanced Research Institute, CAS. He is currently an associate professor and focuses on developing advanced metal-air batteries, electrolyzers, fuel cells, and silicon nanomaterials.