Properties Of Nanostructured Materials Research Articles

Advanced Nanoporous Material–Based QCM Devices: A New Horizon of Interfacial Mass Sensing Technology

AbstractMass interfacial processes have been considered as one of the crucial factors supporting fundamental research. Due to the low cost and conceptual simplicity, significant advancements have been achieved in the development of methodologies based on piezoelectric devices for in situ determination of mass changes on the surfaces of deposited materials under various conditions. The introduction of nanomaterials for designing sensors and monitoring systems becomes essential to create advanced detection systems for selective sensing of toxic analytes for environmental remediation. The integration of materials with predesignated nanostructures into sensor devices, such as surface acoustic wave (SAW), quartz crystal microbalance (QCM), and QCM with dissipation (QCM‐D) monitoring, has led to an immense progress in the sensing applications of toxic target analytes at the nanogram range. Here, an overview is introduced of recent advancement in the fabrication of piezoelectric devices for the interfacial mass sensing of targeted chemical vapors and ions through combination with nanoporous materials including mesoporous materials carbon‐based nanomaterials, metal–organic frameworks (MOFs), MOF‐derived nanoporous carbons, Prussian blue (PB) and its analogues (PBA), zeolites and related materials. Challenges and future prospect are also summarized by the advanced QCM technique associated with properties of nanostructured materials.

COMPUTER MODELING THIN FILM GROWTH ON THE SURFACE BY LOW ENERGY CLUSTER DEPOSITION

A report is presented about progress in the understanding of the properties of bi-metallic nanoparticles, their interaction with surfaces subsequent to low energy slowing down and the properties of nanostructured materials formed with these particles. A nanoparticle contains from a few atoms for the smallest ones to several thousand for the largest ones considered here. The properties of an atom result from quantization and the same is true for the molecules they form. The same is thus true for the smallest nanoparticles. At the other edge, many of the properties of macroscopic materials are well described by a classical approach and nanoparticles appear as objects at the fringing field between quantum and classical behaviors. In the study of their properties, using either a quantum or a classical approach, atomic scale methods appear as naturally well-suited. Atoms are considered as individual objects interacting via their outer shell electrons only. However even with such an approximation, solving the Schrödinger equation becomes quickly prohibitively heavy as the number of atoms involved increases. For the heaviest elements, relativistic effects make the problem even heavier.

Nanostructured Materials for Food Applications: Spectroscopy, Microscopy and Physical Properties.

Nanotechnology deals with matter of atomic or molecular scale. Other factors that define the character of a nanoparticle are its physical and chemical properties, such as surface area, surface charge, hydrophobicity of the surface, thermal stability of the nanoparticle and its antimicrobial activity. A nanoparticle is usually characterized by using microscopic and spectroscopic techniques. Microscopic techniques are used to characterise the size, shape and location of the nanoparticle by producing an image of the individual nanoparticle. Several techniques, such as scanning electron microscopy (SEM), transmission electron microscopy/high resolution transmission electron microscopy (TEM/HRTEM), atomic force microscopy (AFM) and scanning tunnelling microscopy (STM) have been developed to observe and characterise the surface and structural properties of nanostructured material. Spectroscopic techniques are used to study the interaction of a nanoparticle with electromagnetic radiations as the function of wavelength, such as Raman spectroscopy, UV–Visible spectroscopy, attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), dynamic light scattering spectroscopy (DLS), Zeta potential spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray photon correlation spectroscopy. Nanostructured materials have a wide application in the food industry as nanofood, nano-encapsulated probiotics, edible nano-coatings and in active and smart packaging.

Elastic properties of nanostructured materials and their radiation resistance

Young’s modulus of the nc-TiN/a-Si3N4nanocomposite has been calculated depending on a size and a volume fraction of the nanocrystalline phase. The elastic moduli of a-Si3N4matrix and nc-TiN nanocrystals as well as their relation show that they play an important role in the total elastic modulus of the nanocomposite. The kinetics of the defect structure during nanocomposite irradiation was investigated taking into account the recombination processes and sinks on the nanocrystals.

Proteins and Peptides at the Interfaces of Nanostructures.

The present review focuses on the proteins and peptides at the interfaces of nanostructured metals and semiconductors as a result of their use in synthesis in-situ and functionalization of nanostructures. We start the review with an introduction about the peculiar properties of nanostructured materials and their applications. In the following, the chemical and structural properties of peptides and proteins that allow their use as reducing, stabilizing, and functionalization agents are discussed. Proteins and peptides have not only the chemical groups for the metal ion reducing but also provide templates for directing the crystalline growing of nanostructures to the desired shapes and sizes. Proteins and peptides are also used mainly for the stabilization and functionalization of a diversity of nanostructured materials providing properties such as biocompatibility, plasmon-enhanced catalysis, sensing, micro/nanomotors, spin filters, and others. Nanostructured materials of metal oxides have mainly been functionalized with proteins and peptides to gain specific properties such as light harvesting and spin filters. Herein, we described the synthesis and functionalization of some types of nanostructured materials by using peptides and proteins. In the last part of the review, it is discussed the perspectives and challenges for the use of proteins and peptides in Nanotechnology.

Assessment of environmental high-doses using Raman spectroscopy of gamma irradiated MWCNT-OH Nanopowder utilized in radiation accidents

Introduction: The functionalized Multi-Walled Carbon Nanotube with hydroxyl group (MWCNT-OH) due to high aspect ratios (length to diameter), and also excellent mechanical, electrical and thermal characteristics, has great potential applications in flexible electronics, solar cells, antistatic devices, electromagnetic interference shielding, radiation shielding, electrode materials for batteries, lightweight energy storage devices, supercapacitors, piezoelectric sensors, radiation sensors, and dosimeters. Several experiments showed that gamma irradiation can be used to modify the mechanical, and electronic properties of nanostructured carbon materials via the creation of atomic defects in the materials. Raman spectroscopy is a powerful tool for the characterization of carbon nanostructures. According to Raman spectroscopy of nanostructured carbon materials, there are two main peaks of D- band and G-band at 1344 cm-1, 1574 cm-1 respectively. Also there is another peak entitled G' that is indicator of second mode of vibrations in the carbon atoms near 2680 cm-1. The ratio of ID/IG is a characterizing agent for determination of structural defects created in carbon nanostructures. It is expected to increase the amount of ID/IG after gamma irradiation of MWCNT-OH sample at high dose irradiations. Regarding this fact, if the plot of ID/IG versus absorbed dose would be linear, so it can be deduced that this material can be used as a dosimeter. Materials and Methods: In this experimental work, MWCNT-OH Nanopowder with density of 2.1 g/cm3, the outer diameter of 5-15 nm, the inner diameter of 3-5 nm, 50 μm length, the electrical conductivity between 105-107 S/m, containing 1.7 wt% –OH groups was prepared from US Nano Inc and irradiated by gamma rays of 60Co gamma-cell installed in Atomic Energy Organization of Iran-Tehran with dose rate of 1.62 Gy/s within the different doses of 0-30 kGy at room temperature. Raman spectroscopy model Takram P50C0R10 with 532 nm Nd:YAG laser in the range of 100–4600 was applied. Results: According to Raman spectroscopy of the samples, the ratio of ID/IG versus absorbed dose exhibited a linear response in the range of 0-20 kGy and after that saturation effect was dominant. The maximum increase in the ID/IG value in comparison with pristine sample was ±18.7 % at 20 kGy. Conclusion: In this experimental work, MWCNT-OH Nanopowder was prepared and irradiated by gamma rays in different doses of 0-30 kGy at room temperature. The samples were subjected to Raman spectroscopy to determine the defects created in the carbon atoms of the nanostructure materials. Results showed that the amount of ID/IG versus absorbed dose exhibited a linear behavior in the range of 0-20 kGy that can be used for high dose level dosimetry purposes especially assessment of dose in the radiation accidents at nuclear facilities.

Nanostructured Metallic Materials and Composites: Processes, Properties and Microstructures

Nanostructured Metallic Materials and Composites: Processes, Properties and Microstructures

Graphene-Coated Honeycomb for Broadband Lightweight Absorbers

The development of lightweight microwave absorber, operating in a wide range of frequencies, is still a challenging task. A novel broadband lightweight radar absorbing material is developed using a phenolic aramid honeycomb (HC) coated with a graphene-filled polymeric paint, which is made of a colloidal suspension of graphene nanoplatelets (GNPs) dispersed in a mixture of polyvinyl-alcohol, water, and 1-propanol. This study describes the production process of the GNP-filled paint and of the lossy HC, and investigates the morphological and electromagnetic properties of the new nanostructured material. A multiscale effective-medium model of the GNP-coated HC, which takes into account the morphology and properties of the nanostructured material from micro- to macroscale, is developed and validated through the comparison with experimental data in the X -band. Findings demonstrate a feasible way to develop lightweight and broadband absorbers for various practical applications.

Special issue on thermoelectric properties of nanostructured materials

R R acknowledges financial support by the Ministerio de Economia, Industria y Competitividad (MINECO) under grant FEDER-MAT2017-90024-P and the Severo Ochoa Centres of Excellence Program under Grant SEV-2015-0496 and by the Generalitat de Catalunya under Grant No. 2017 SGR 1506. C Y acknowledges financial support from the Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2018M3D1A1057844). I Z acknowledges financial support from the Swiss National Science Foundation research grant (Project Grant No. 200021_165784).

C&EN talks with Amy Prieto, battery innovator

Amy Prieto decided to pursue battery research when she started as an assistant professor of chemistry at Colorado State University in 2005. The field was a perfect bridge between her Ph.D. studies in solid-state materials for electronic devices and her postdoctoral work in measuring transport properties of nanostructured materials. It turned out to be a fruitful decision. She has patented novel battery materials and a unique manufacturing process that together revamp decades-old lithium-ion technology. Her lithium-ion battery, built on a foundation of electroplated copper foam, is more flexible, safer, less expensive, and more environmentally friendly than batteries currently on the market. In 2009, just four years after embarking on her research, she founded a company, Prieto Battery, to develop the technology for commercial use. The start-up caught the eyes of the power-tool manufacturer Stanley Black & Decker and the computer technology giant Intel, both of which invested in the technology

A critical study of the parameters governing molecular dynamics simulations of nanostructured materials

Molecular dynamics (MD) simulations have been used extensively over the past two decades to determine the mechanical and physical properties of nanomaterials. However, the discrepancy between the reported results from these atomistic studies shadows the reliability of this computationally efficient technique. This inconsistency is attributed to the misuse and incorrect application of MD as evidenced by the arbitrary use of interatomic potentials, cut-off function parameters, strain rate, time increment, and domain size in the conducted simulations. In this paper, we highlight erroneous simulations by investigating the influence of these parameters on the elastic and fracture properties of nanostructured materials; including carbon nanotubes, graphene, and boron nitride (BN) sheets subject to direct and contact loads. The effect of interatomic potential type was investigated by comparing the predicted properties from AIREBO, Tersofff, CVFF, and ReaxFF potentials with those obtained with experimental and DFT techniques. The cut-off function parameters were also investigated to determine the optimum inner and outer cut-off radii selected to capture the actual physical behavior and avoid the reported strain hardening phenomena. Furthermore, MD simulations with strain rates spanning several orders of magnitudes and time increments ranging from 0.1 to 20 fs were performed to define the maximum allowable parameters for each material and loading scheme. Additionally, graphene and BN sheets with side length up to 500 Å were modeled to determine the size and edge effects on the mechanical properties. Finally, a set of parameters is recommended in each investigation to help guiding future atomistic studies obtaining reliable results using the available computational resources.

Mechanical Synthesis and Rapid Consolidation of Nanostructured W-Al2O3 Composite

Recently, the properties of nanostructured materials as advanced engineering materials have received great attention. These properties include fracture toughness and a high degree of hardness. To hinder grain growth during sintering, it is necessary to fabricate nanostructured materials. In this respect, a high-frequency induction-heated sintering method has been presented as an effective technique for making nanostructured materials at a lower temperature in a very short heating period. Nanopowders of W and Al2O3 are synthesized from WO3 and Al powders during high-energy ball milling. Highly dense nanostructured W-Al2O3 composites are made within three minutes by high-frequency induction-heated sintering method and materials are evaluated in terms of hardness, fracture toughness, and microstructure. The hardness and fracture toughness of the composite are 1364 kg/mm2 and 7.1 MPa·m1/2, respectively. Fracture toughness of nanostructured W-Al2O3 is higher than that of monolithic Al2O3. The hardness of this composite is higher than that of monolithic W.

Lattice Heat Capacity of Nanostructured Materials Based on Titanium/Zirconium and Aluminum

The dynamic and thermal properties of nanostructured materials based on aluminum with the periodic inclusions of Ti or Zr clusters have been investigated by the method of molecular dynamics. The elastic moduli, spectral vibrational densities of states, and temperature dependences of heat capacity for different Ti–Al and Zr–Al systems have been obtained. The effect of specific features of the phonon spectrum on the heat capacity of the nanocomposite lattice has been examined. It is shown that the ordering type and size of Ti/Zr clusters in the aluminum matrix significantly affect the elastic properties and heat capacity. The results obtained can be used for fabricating new aluminum-, titanium-, and zirconium-based composites with the desired properties.

Transition from poor ductility to room-temperature superplasticity in a nanostructured aluminum alloy

Recent developments of nanostructured materials with grain sizes in the nanometer to submicrometer range have provided ground for numerous functional properties and new applications. However, in terms of mechanical properties, bulk nanostructured materials typically show poor ductility despite their high strength, which limits their use for structural applications. The present article shows that the poor ductility of nanostructured alloys can be changed to room-temperature superplastisity by a transition in the deformation mechanism from dislocation activity to grain-boundary sliding. We report the first observation of room-temperature superplasticity (over 400% tensile elongations) in a nanostructured Al alloy by enhanced grain-boundary sliding. The room-temperature grain-boundary sliding and superplasticity was realized by engineering the Zn segregation along the Al/Al boundaries through severe plastic deformation. This work introduces a new boundary-based strategy to improve the mechanical properties of nanostructured materials for structural applications, where high deformability is a requirement.

Influence of Growth Mechanism and Potential Cycling on the Active Surface Area of Electrodeposited Highly Porous Pt Nanoparticles

It is widely known that nanostructured materials are one of the key elements in the recent advances of various technological fields. More precisely, energy conversion devices (fuel cells, batteries, solar cells, etc.) have seen their efficiency boosted thanks to the engineering of materials in the nanoscale. The efficiency of these processes depends on many factors. Among them, increasing the surface to volume ratio (SVR) of the active materials is sought after in most energy conversion technologies. Moreover, large active surface areas are also targeted for highly sensitive (bio)sensors. Hence, optimizing the surface properties of nanostructured materials is of great interest. In this work, we explored different electrochemical deposition procedures and experimental conditions to obtain distributions of Pt nanostructures with large surface areas. Furthermore, to evaluate the available Pt surface, in addition to conventional hydrogen underpotential deposition (H UPD), we used high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and quantitative 3D electron tomography [1, 2]. Pt dendritic nanoparticles (NPs) with large surface area were successfully electrodeposited using a potentiostatic double-pulse procedure under forced convection. Large nucleation overpotential led to a large surface coverage of roughened spheroids, providing a large roughness factor (Rf) but low mass-specific electrochemically active surface area (EASA). Lowering the nucleation overpotential led to highly porous Pt NPs with pores stretching to the center of the structure. At the expense of smaller Rf, the obtained EASA values of these structures were in the range of those of large surface area supported fuel cell catalysts. The active surface area of the Pt dendritic NPs was measured by electron tomography, and it was found that the potential cycling in the H adsorption/desorption and Pt oxidation/reduction region, which is generally performed to determine the EASA, led to a significant reduction of that surface area due to a partial collapse of their dendritic and porous morphology. Interestingly, the extrapolation of the microscopic tomography results in macroscopic electrochemical parameters indicated that the surface properties measured by H UPD were comparable to the values measured on individual NPs by electron tomography after the degradation caused by the H UPD measurement. These results highlighted that the combination of electrochemical and quantitative 3D surface analysis techniques is essential to provide insights into the surface properties, the electrochemical stability, and, hence, the applicability of these materials. Moreover, it indicated that care must be taken with widely used electrochemical methods of surface area determination, especially in the case of large surface area and possibly unstable nanostructures, since the measured surface can be strongly affected by the measurement itself. [1] B. Geboes, J. Ustarroz, K. Sentosun, H. Vanrompay, A. Hubin, S. Bals, T. Breugelmans, ACS Catalysis, 6 (9) (2016) 5856-5864. [2] J. Ustarroz, B. Geboes, H. Vanrompay, K. Sentosun, S. Bals, T. Breugelmans, A. Hubin, ACS Applied Materials & Interfaces, 9 (19) (2017) 16168-16177.

Adsorptive Recovery of Auro-Dicyanide Anions from Aqueous Solutions using Activated Carbon-Magnesium Oxide (C-MgO) Nanocomposite as Adsorbent

ABSTRACTThe reprocessing of tailings or gold mine waste dumps to extract gold has become an attractive proposition for mining houses worldwide because of the availability of gold which was not easily recovered using old technologies. This study seeks to exploit the novel properties of nanostructured materials in enhancing gold extraction from gold mine tailings. The beneficiation of slimes or tailings involved taking samples for mineralogical studies, synthesis of a novel adsorbent medium (nano C-MgO) prepared by using both chemical and mechano-synthesis methods, oxidative pre-treatment of flotation concentrates, cyanidation and final recovery of the precious metal from solution in a Carbon in Column (CIC) system. The nanocomposite adsorbent was studied by powder X-ray Diffraction (XRD) for structural analysis, Field Emission Scanning Electronic Microscopy (FESEM) for surface morphology, Energy-dispersive X-ray spectroscopy (EDX) for elemental analysis and Fourier Transform Infrared (FTIR) spectroscopy for chemical structure analysis. The Brunauer-Emmett-Teller (BET) Surface Area Analysis procedure was employed to determine the total specific surface area of the nano-adsorbent. Representative tailings samples of 100-500 g were obtained for different analytical investigations using a riffle splitter. The tailings grade was analysed using the Atomic Absorption Spectroscopy (AAS) technique and was found to be an average of 0.5 g/tonne. A comparative Pseudo-Equilibrium test showed that the novel C-MgO nano adsorbent had an average of 84% recovery against 70 % for convectional activated carbon. The average crystalline size of 4.5 -11nm for the majority of MgO nanoparticles was obtained using Debye-Scherrer formula. FESEM confirmed that nano MgO was porous in nature and highly agglomerated whilst EDX exhibited the successful synthesis of the nano-composite product. This work also shows that the nano-adsorbent presents a huge potential for application in the conventional processes for gold adsorption.

A Comparative Study of Chemically and Biologically Synthesized MgO Nanomaterial for Liquefied Petroleum Gas Detection

The exceptional chemical and physical properties of nanostructured materials are extremely suitable for designing new and enhanced sensing devices, particularly gas sensors and biosensors. The present work describes the synthesis of magnesium oxide (MgO) nanoparticles through two methods: a green synthesis using aloe vera plant extract and a chemical method using a glycine-based solution combustion route. In a single step, the extracted organic molecules from aloe vera plants were used to reduce metal ions by the green method. MgO nanoparticles were coated onto the interdigital electrode using the drop-drying method. The dynamic gas-sensing characteristics were measured for liquefied petroleum gas (LPG) at different concentrations and various temperatures. The MgO nanoparticles were characterized by using x-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy to determine the size and structure of the particles. The product’s functional properties were analyzed by Fourier transform-infrared spectroscopy and UV–visible spectroscopy. We found that the LPG sensing behavior of biologically synthesized MgO registers excellent sensitivity at various operating temperatures.

Synthesis and characterization of hausmannite (Mn3O4) nanostructures

Hausmannite (Mn3O4) plate like nano-grains, coin like nano-sphere and nano-petals structure were respectively prepared employing co-precipitation, sol-gel and hydrothermal route. The obtained product was characterized comprehensively. High specific capacitance value of 462.70 F/g at 10 mV/s was achieved using hydrothermal method. The magnetic behavior of product both in ZFC and FC modes employing VSM study confirmed the paramagnetic behavior turned as ferrimagnetic while changed the mode from ZFC to FC. The product synthesized by hydrothermal method possessed the good coercivity value of about 1965 Oe at 5 K. The preparation protocols have dominant influence on structural, morphological, optical, electrochemical and magnetic properties of nanostructured materials.

Решеточная теплоемкость наноструктурированных материалов на основе титана/циркония и алюминия

AbstractThe dynamic and thermal properties of nanostructured materials based on aluminum with the periodic inclusions of Ti or Zr clusters have been investigated by the method of molecular dynamics. The elastic moduli, spectral vibrational densities of states, and temperature dependences of heat capacity for different Ti–Al and Zr–Al systems have been obtained. The effect of specific features of the phonon spectrum on the heat capacity of the nanocomposite lattice has been examined. It is shown that the ordering type and size of Ti/Zr clusters in the aluminum matrix significantly affect the elastic properties and heat capacity. The results obtained can be used for fabricating new aluminum-, titanium-, and zirconium-based composites with the desired properties.

Centimeter-Long Single-Crystalline Si Nanowires.

The elongation of free-standing one-dimensional (1D) functional nanostructures into lengths above the millimeter range has brought new practical applications as they combine the remarkable properties of nanostructured materials with macroscopic lengths. However, it remains a big challenge to prepare 1D silicon nanostructures, one of the most important 1D nanostructures, with lengths above the millimeter range. Here we report the unprecedented preparation of ultralong single-crystalline Si nanowires with length up to 2 cm, which can function as the smallest active material to facilitate the miniaturization of macroscopic devices. These ultralong Si nanowires with augmented flexibility are of emerging interest for flexible electronics. We also demonstrate the first single-nanowire-based wearable joint motion sensor with superior performance to reported systems, which just represents one example of novel devices that can be built from these nanowires. The preparation of ultralong Si nanowires will stimulate the fabrication and miniaturization of electric, optical, medical, and mechanical devices to impact the semiconductor industry and our daily life in the near future.