Micro-and Nanoscale Research Articles

Microfluidics on lensless, semiconductor optical image sensors: challenges and opportunities for democratization of biosensing at the micro-and nano-scale

Abstract Optical image sensors are 2D arrays of pixels that integrate semiconductor photodiodes and field effect transistors for efficient photon conversion and processing of generated electrons. With technological advancements and subsequent democratization of these sensors, opportunities for integration with microfluidics devices are currently explored. 2D pixel arrays of such optical image sensors can reach dimensions larger than one centimeter with a sub-micrometer pixel size, for high spatial resolution lensless imaging with large field of view, a feat that cannot be achieved with lens-based optical microscopy. Moreover, with advancements in fabrication processes, the field of microfluidics has evolved to develop microfluidic devices with an overall size below one centimeter and individual components of sub-micrometer size, such that they can now be implemented onto optical image sensors. The convergence of these fields is discussed in this article, where we review fundamental principles, opportunities, challenges, and outlook for integration, with focus on contact-mode imaging configuration. Most recent developments and applications of microfluidic lensless contact-based imaging to the field of biosensors, in particular those related to the potential for point of need applications, are also discussed.

Pulsatile pressure enhanced rapid water transport through flexible graphene nano/Angstrom-size channels: a continuum modeling approach using the micro-structure of nanoconfined water

Several researchers observed a significant increase in water flow through graphene-based nanocapillaries. As graphene sheets are flexible (Wang and Shi 2015 Energy Environ. Sci. 8 790–823), we represent nanocapillaries with a deformable channel-wall model by using the small displacement structural-mechanics and perturbation theory presented by Gervais et al (2006 Lab Chip 6 500–7), and Christov et al (2018 J. Fluid Mech. 841 267–86), respectively. We assume the lubrication assumption in the shallow nanochannels, and using the microstructure of confined water along with slip at the capillary boundaries and disjoining pressure (Neek-Amal et al 2018 Appl. Phys. Lett. 113 083101), we derive the model for deformable nanochannels. Our derived model also facilitates the flow dynamics of Newtonian fluids under different conditions as its limiting cases, which have been previously reported in literature (Neek-Amal et al 2018 Appl. Phys. Lett. 113 083101; Gervais et al 2006 Lab Chip 6 500–7; Christov et al 2018 J. Fluid Mech. 841 267–86 ; White 1990 Fluid Mechanics; Keith Batchelor 1967 An Introduction to Fluid Dynamics ; Kirby 2010 Micro-and Nanoscale Fluid Mechanics: Transport in Microfluidic Devices). We compare the experimental observations by Radha et al (2016 Nature 538 222–5) and MD simulation results by Neek-Amal et al (2018 Appl. Phys. Lett. 113 083101) with our deformable-wall model. We find that for channel-height Å, the flow-rate prediction by the deformable-wall model is 5%–7% more compared to Neek-Amal et al (2018 Appl. Phys. Lett. 113 083101) well-fitted rigid-wall model. These predictions are within the errorbar of the experimental data as shown by Radha et al (2016 Nature 538 222–5), which indicates that the derived deformable-wall model could be more accurate to model Radha et al (2016 Nature 538 222–5) experiments as compared to the rigid-wall model. Using the model, we study the effect of the flexibility of graphene sheets on the flow rate. As the flexibility α increases (or corresponding thickness and elastic modulus E of the wall decreases), the flow rate also increases. We find that the flow rate scales as for ; for ; and for , respectively. We also find that, for a given thickness , the percentage change in flow rate in the smaller height of the channel is more than the larger height of the channels. As the channel height decreases for the given reservoir pressure and thickness, the increases with followed by after a height-threshold. Further, we investigate how the applied pulsating pressure influences the flow rate. We find that due to the oscillatory pressure field, there is no change in the averaged mass flow rate in the rigid-wall channel, whereas the flow rate increases in the flexible channels with the increasing magnitude of the oscillatory pressure field. Also, in flexible channels, depending on the magnitude of the pressure field, either of the steady or oscillatory or both kinds of pressure field, the averaged mass flow rate dependence varies from to as the pressure field increases. The flow rate in the rigid-wall channel scales as , whereas for the deformable-wall channel it scale as for , for , and for . We find that both the flexibility of the graphene sheet and the pulsating pressure fields to these flexible channels intensify the rapid flow rate through nano/Angstrom-size graphene capillaries.

Editorial: Probing out-of-equilibrium soft matter

of soft matter is amply studied and understood, novel tools are needed to capture the complexity of out-of-equilibrium soft materials. A particular challenge is getting access to and understanding the fast processes occurring at the nano-and micro-scale of the elementary constituents, while simultaneously capturing the slower evolution of bulk properties in non-equilibrium conditions. To take on this task, new theoretical, numerical and experimental methodologies need to be developed that enable the investigation of the structure, dynamics, thermodynamics, and rheology of out-of-equilibrium soft matter. Adopting a comprehensive view that covers fundamental topics as well as research focusing on processes and issues faced in applications, this Research Topic aims to showcase some of the latest advancements and innovations in the field.Living and active materials are intrinsically non-equilibrium systems due to metabolic activity and/or energy consumption. Using newly developed fabrication and image processing tools, Chang et al.

Simultaneous Micro- and Nanoscale Silicon Fabrication by Metal-Assisted Chemical Etch

Abstract Simultaneous micro- and nanoscale etching of silicon on a wafer-scale is nowadays performed using plasma etching techniques. These plasma techniques, however, suffer from low throughput due to aspect-ratio dependent etch (ARDE) rate, etch lag from changes in feature size, loading effects from increased etch area, and undesirable surface characteristics such as sidewall taper and scalloping, which are particularly problematic at the nanoscale and can affect the etch uniformity. Additionally, the hardware required for plasma etching can be very expensive. A potential alternative, which addresses the above issues with plasma etching is metal assisted chemical etch (MacEtch). To date, however, an integrated micro- and nanoscale MacEtch process, which has uniform and clean (i.e., without nanowire-like defects in microscale areas) etch front has not been presented in the literature. In this work, we present for the first time a feasible process flow for simultaneous micro-and nanoscale silicon etching without nanowire-like defects, which we call integrated micro- and nanoscale MacEtch (IMN-MacEtch). Successful etching of silicon features ranging from 100 nm to 100 μm was achieved with etch rates of about 1.8 μm/min in a single step to achieve features with an aspect ratio (AR) ∼18:1. We thus conclude that the process represents a feasible alternative to current dry etch methods for patterning feature sizes spanning three orders of magnitude.

Engineering multiscale polypyrrole/carbon nanotubes interface to boost electron utilization in a bioelectrochemical system coupled with chemical absorption for NO removal.

The chemical absorption-bioelectrochemical reduction (CABER) integrated system provides an alternative of good potential for NO removal. The efficient utilization of cathode electrons directly determines the system performance and operating cost. Herein, we synthesize a polypyrrole/carbon nanotubes (PPy/CNTs) composite to engineer a micro-and nanoscale interface with low resistance and high biocompatibility between the cathode and biofilms in the CABER system. The resulting PPy/CNTs biocathodes exhibit 36.4% increase in biomass density, 40.7%-302.6% increase in Faraday efficiency along Fe(III)EDTA reduction, and 204% increase in Fe(II)EDTA-NO reduction rate. The enrichment of functional microorganisms is validated to be a key strengthening factor, as the proportion of which increased from 57.9% to 84.6%. Moreover, for efficient electron transfer and utilization, a low-resistance electron transfer route, "electrode substrate → PPy (→ CNTs) → microbial cells → Fe(III)EDTA or Fe(II)EDTA-NO", is realized in the multiscale conductive networks constructed of PPy/CNTs composite and microbial nanowires.

Nanoscale Control of Hydrated Portland Cement Structure

The durability of cement-containing building materials, like the cement stone itself, depends on their moisture resistance, frost resistance, and corrosion resistance. All these properties are determined not only by the composition of the initial clinker, but also by the structural organization at the micro-and nanoscale of hydrated Portland cement. In this work, the structural parameters of hydrated Portland cement compositions at the nanoscale level were determined by the method of small-angle neutron scattering: the size distribution of nanoparticles of calcium silicate hydrate, the average radius of nanoparticles, and fractal dimension. It is shown that the introduction of modifying nanoadditives into Portland cement affects the structural parameters of the cement stone. The following nanoadditives were used: of artificial (alpha aluminium oxide, gamma aluminum oxide) and of technogenic (carbonate and alumo-alkaline sludges) origin, as well as complex nanoadditives containing surfactants. Changes in structural parameters of Portland cement with nanoadditives in the process of hydration are traced. It is shown that the use of nanoadditives makes it possible to control the process of formation of the structure of hydrated Portland cement on the nanoscale level, to directly influence the values of structural parameters and, ultimately, to the properties of cement stone.

Magnetically tunable bandgaps in phononic crystal nanobeams incorporating microstructure and flexoelectric effects

A new triple-layer phononic crystal (PC) composite beam model is proposed, which binds two piezomagnetic layers to conventional PCs coupling the microstructure and flexoelectric effects. A variational approach is employed to derive the relevant equations of motion and boundary conditions (BCs), followed by using the Bloch theory and transfer matrix method (TMM) to accurately calculate the bandgap of elastic waves. Numerical results show that the microstructure and flexoelectric effects elevate the bandgap frequency at the micro-and nano-scales, respectively, but both can be neglected at the macroscale. The thickness of the piezomagnetic layers and the volume fraction of the PC play an important role in the generation of the bandgap. With the help of the piezomagnetic layers, tunable bandgaps can be obtained by adjusting the external magnetic potential field at all scales. This paper provides an innovative idea for flexoelectric-based PC devices designing when magnetic fields are involved.

Biomimicked large-area anisotropic grooves from Dracaena sanderiana leaf enhances cellular alignment and subsequent differentiation

Cellular alignment is important for the proper functioning of different tissues such as muscles or blood vessel walls. Hence, in tissue engineering, sufficient effort has been made to control cellular orientation and alignment. It has been shown that micro-and nanoscale anisotropic topological features on cell culture substrates can control cellular orientation. Such substrates are fabricated using various lithography techniques such as photolithography and soft lithography. Although such techniques are suitable for creating patterns in small areas to establish a proof-of-concept, patterning large areas with intricate features is an unsolved problem. In this work, we report that a replica of the groove-like anisotropic patterns of the abaxial side of a Dracaena sanderiana (bamboo) leaf can be used for large-area patterning of cells. We imprinted the leaf on polydimethylsiloxane (PDMS) and characterised its surface topography using scanning electron microscopy. We further cultured bone marrow human mesenchymal cells (BM-hMSCs), skeletal muscle cells (C2C12), and neuroblastoma cells (SHSY5Y) on the patterned PDMS on which the cells orient along the direction of the grooved pattern. Further, we observed enhanced neuronal differentiation of SHSY5Y cells on biomimicked pattern compared to flat PDMS as measured by percentage of cells with neurites, neurite length and the expression of neuronal differentiation marker beta-III tubulin (TUJ1). This process is simple, frugal, and can be adopted by laboratories with resource constraints. This one-step technique to fabricate large-area anisotropic surface patterns from bamboo leaves can be used as a platform to study cellular alignment and its effect on various cellular functions, including differentiation.

Migration of water and ions in nanopores under different ion-ion correlation strength condition

Migration of moisture and ions in C-S-H nanopores is restricted due to the prominence of interfacial effect and intermolecular forces. This paper provided a migration model of water and chloride ions considering ion correlation, dual interface slip and time-varying characteristics of Electrical Double Layer (EDL), which based on governing equations and boundary conditions of nano-flow as well as the hierarchical structure and transport mechanism of restricted liquids. In the paper, the wettability of the C-S-H surface was investigated by conducting contact angle experiments on the synthesized single-phase C-S-H, then the distribution characteristics of water and ions were described in combination with the properties of restricted liquids. By introducing slip length and velocity, the slip between solid-liquid interfaces and the slip between liquid layers near the wall were described. The time-varying properties of the double layer are described by introducing Einstein-Stokes equation and Modified Poisson-Boltzmann equation. Based on AFM, wedge coefficient was introduced into the model to characterize the pore morphology. The results show that the contribution ratio of slip and time-varying of EDL can reach about 70% and 20%, respectively and this phenomenon is more significant in smaller pore size. There are large differences in small and large pore sizes for the phenomena caused by different ion correlation strength conditions. Under strong ion correlation, the influence of water film slip is weakened by 8–10% due to the existence of strong adhesion between solid-liquid interface. The findings provided a systematic insight into the micro-and nanoscale flow.

Application of advanced (S)TEM methods for the study of nanostructured porous functional surfaces: A few working examples

Nanostructured films offer the ability of modifying surface properties, even more, when they can generate layers with controlled porosity. The lower implicit integrity of these (multi)layers when compared to their compact counterparts, hinders the attainment of electron-transparent sections of submicron thicknesses (lamellae), which becomes one of the main reason for the scarcity of studies thorough (scanning-)transmission electron microscopy ((S)TEM). Aware of this opportunity, this report provides an overview of the possibilities offered by the application of a variety of (S)TEM techniques for the study of nanostructured and porous photonic surfaces. A few working examples are presented to illustrate the type of information that can be obtained in the case of mesoporous films prepared either by at oblique angles physical processes as well as nitride nanowire arrays prepared by epitaxy methods. It will be demonstrated that this approach enables the realization of several pioneering works, which are essential to complete the characterization of such porosity-controlled coatings. Topics as diverse as the preparation of electron-transparent specimens and the advanced characterization of their structures, morphologies, interfaces and compositions are addressed thanks to the implementation of new breakthroughs in (S)TEM, which allow to obtain high-resolution imaging, spectroscopies, or tomography, at both microscopic and nanoscopic levels. Finally, establishing (S)TEM as a reference tool for the advanced structural, chemical and morphological characterization of porous nanostructured skins, will open new horizons, providing better and new insights and thus allowing the optimization of the fabrication and design of such architectures. • Advanced (S)TEM studies of porous nanostructured coatings at micro-and nanoscale • Preparation of electron-transparent lamellae of porous layers of diverse materials • Crystal structure surveys by HRTEM and STEM-iDPC methods • Chemical compositional analyses by STEM-EDX and STEM-EELS • 3D reconstructions and porosity/depth profiles by STEM-HAAF tomography

PTH 1-34-functionalized bioactive glass improves peri-implant bone repair in orchiectomized rats: Microscale and ultrastructural evaluation

The objective of this work was to investigate the use of Biogran® functionalized with parathyroid hormone (PTH) 1–34 by sonochemistry for the local delivery of this anabolic agent to the implant site. The effects of Biogran® and topical administration of PTH 1–34 on peri-implant bone regeneration were evaluated from the microscale to ultrastructural levels in healthy (SHAM) and orchiectomized (ORQ). While some animals only received a titanium implant in their tibial metaphyses (CLOT group), in others the peri-implant defect was first filled with Biogran® either without or with PTH 1–34 functionalization (BG and BGPTH groups, respectively) prior to implant installation. Osseointegration was characterized from a biomechanical perspective by measuring the removal torque with the counter-torque technique. Micro-CT was used to evaluate the percentage of bone volume, trabecular thickness, number and separation, and bone-implant contact (BIC). Dynamics of new bone formation were assessed by measuring fluorochrome area, daily mineral apposition rate, and neoformed bone area using confocal laser microscopy. RT-PCR was performed to evaluate ALP and osteocalcin expression. The interface between newly formed bone and Biogran® was examined using scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) at the micro-and nanoscale, respectively, while elemental analyses were completed in SEM with energy-dispersive X-ray spectroscopy (EDS). STEM imaging demonstrated the intimate attachment of bone to Biogran® (nanoscale level). Overall, the results suggest that the effectiveness of the topical administration of PTH 1–34 at the implant site seems enhanced in osteoporotic bone, promoting peri-implant bone regeneration to comparable levels in healthy conditions.

The research of local and average heat transfer while condensation on a horizontal pipe with a microand nanoscale coating

The research of local and average heat transfer while condensation on a horizontal pipe with a microand nanoscale coating

Bacterial Journey of Micro- and Nano-adsorption mechanisms for Chromate Elimination: A Prospective Study

Chromium (VI) is extensively used in the leather and mining industries for various purposes. These industries release large volumes of untreated effluent containing a higher percentage of toxic Cr (VI) into the environment leading to adverse ecological and health problems. Cr (VI) compounds are recognized as highly carcinogenic, teratogenic and mutagenic to living organisms. Conventional approaches for chromate remediation are uneconomical or produce large quantities of toxic chemical wastes. Microbial remediation at the micro-and nano-scale provides a safe, flexible, inexpensive and eco-friendly strategy for the removal of chromate. This approach reduces the bioavailability of chromate ions to living organisms. It was perceived that the transformation and precipitation of Cr (VI) by microbial metabolic activities are very effective in this perspective. Biosorption is developing as an important integrated approach to treat industrial effluents containing higher amounts of Cr (VI) compounds. Microorganisms, for example, bacteria, fungi and algae used as biosorbents/ bio-materials for Cr (VI) removal have received great interest due to low cost, easy availability, high surface-to-volume ratio and rapid kinetics of adsorption and desorption. This review summarizes Cr (VI) remediation mechanisms by bacteria and integrates these microbes with nanotechnology such as carbon-nanotubes infused into calcium alginate, which considerably enhances the chromate reduction from an aqueous environment. Furthermore, it also discusses the significance of biomaterials and biosorption technology involved in chromate detoxification.

Convergence of micro-geochemistry and micro-geomechanics towards understanding proppant shale rock interaction: A Caney shale case study in southern Oklahoma, USA

As a direct outcome of economic development coupled with an increase in population, global energy demand will continue to rise in the coming decades. Although renewable energy sources are increasingly investigated for optimal production, the immediate needs require focus on energy sources that are currently available and reliable, with a minimal environmental impact; the efficient exploration and production of unconventional hydrocarbon resources is bridging the energy needs and energy aspirations, during the current energy transition period. The main challenges are related to the accurate quantification of the critical rock properties that influence production, their heterogeneity and the multiscale driven physico-chemical nature of rock–fluid interactions. A key feature of shale reservoirs is their low permeability due to dominating nanoporosity of the clay-rich matrix. As a means of producing these reservoirs in a cost-effective manner, a prerequisite is creation of hydraulic fracture networks capable of the highest level of continued conductivity. Fracturing fluid chemical design, formation brine geochemical composition, and rock mineralogy all contribute to swelling-induced conductivity damage. The Caney Shale is an organic-rich, often calcareous mudrock. Many studies have examined the impact that clay has on different kinds of shale productivity but there is currently no data reported on the Caney Shale in relation to horizontal drilling; all reported data on the Caney Shale is on vertical wells which are shallow, compared to an emerging play that is at double the depth. In this work we develop geochemical–geomechanical integration of rock properties at micro-and nanoscales that can provide insights into the potential proppant embedment and its mitigation. The novel methodology amalgamates the following: computed X-ray tomography, scanning electron microscopy, energy dispersive spectroscopy, micro-indentation, and Raman spectroscopy techniques. Our results show that due to the multiscale heterogeneity in the Caney Shale, these geochemical and structural properties translate into a variation in mechanical properties that will impact interaction between the proppant and the host shale rock.

Pressure-Driven Nitrogen Flow in Divergent Microchannels with Isothermal Walls

Gas flow and heat transfer in confined geometries at micro-and nanoscales differ considerably from those at macro-scales, mainly due to nonequilibrium effects such as velocity slip and temperature jump. Nonequilibrium effects increase with a decrease in the characteristic length-scale of the fluid flow or the gas density, leading to the failure of the standard Navier–Stokes–Fourier (NSF) equations in predicting thermal and fluid flow fields. The direct simulation Monte Carlo (DSMC) method is employed in the present work to investigate pressure-driven nitrogen flow in divergent microchannels with various divergence angles and isothermal walls. The thermal fields obtained from numerical simulations are analysed for different inlet-to-outlet pressure ratios (1.5≤Π≤2.5), tangential momentum accommodation coefficients, and Knudsen numbers (0.05≤Kn≤12.5), covering slip to free-molecular rarefaction regimes. The thermal field in the microchannel is predicted, heat-lines are visualised, and the physics of heat transfer in the microchannel is discussed. Due to the rarefaction effects, the direction of heat flow is largely opposite to that of the mass flow. However, the interplay between thermal and pressure gradients, which are affected by geometrical configurations of the microchannel and the applied boundary conditions, determines the net heat flow direction. Additionally, the occurrence of thermal separation and cold-to-hot heat transfer (also known as anti-Fourier heat transfer) in divergent microchannels is explained.

Microfluidic synthesis of chitosan-coated magnetic alginate microparticles for controlled and sustained drug delivery

The present work aimed to assemble a simple, portable and economical L-junction microfluidic device to realize the adjustment and tunability of homogeneous round-shaped particles synthesis. In this study, we synthesize two kind of microparticles, including magnetic alginate microparticles (MAM) and chitosan-coated magnetic alginate (CMAM) used for controlling the drug release under a mild condition. Comparing to the traditional method, the MAM synthesized via this microfluidic approach has uniform size distribution, adjustable diameter as well as tunable magnetism. By exploring the amoxicillin as model drug, the MAM displays excellent pH-sensitive release, the effect of particle size on the drug release rate was investigated as well. The results show the smaller particles (220 μm) show a faster release rate than the bigger materials (1000 μm) due to their larger specific area, providing more frequency to interact with the reaction solution. The positive polyelectrolyte, chitosan, coated on the magnetic alginate surface endows CMAM time extension in drug release by two times, successfully achieving drug controlled and sustained release via the kinetics analysis. In summary, this microfluidic approach provides a convenient and efficient fluidic design for the well-controlled synthesis of micro-and nanoscale particles, which is a potential choice used for controlled and sustained drug release.

Development of Executive Equipment Design for Implementing the Process of Generating of Drops of Microand Nanoscale Range

Modeling of velocities and temperatures processes distribution in the plasma-forming channel determining the design features and optimal parameters of the plasma torch nozzle is one of promising directions in development of plasma technologies. The aim of this work was to simulate the processes of velocities and temperature distribution in the plasma-forming channel and to determine the design features and optimal geometric parameters of the plasmatron nozzle which ensures the formation of necessary direction of plasma flows for generation of surface waves on the surface of a liquid metal droplet under the influence of the investigated instabilities.One of the main tasks is to consider the process of plasma jet formation and the flow of electric arc plasma. For obtaining small-sized particles one of the main parameters is the plasma flow velocity. It is necessary that the plasma outflow velocity be close to supersonic. An increase of the supersonic speed is possible due to design of the plasmatron nozzle especially the design feature and dimensions of the gas channel in which the plasma is formed. Also the modeling took into account dimensions of the plasma torch nozzle, i. e. the device should provide a supersonic plasma flow with the smallest possible geometric dimensions.As a result models of velocities and temperatures distribution in the plasma-forming channel at the minimum and maximum diameters of the channel were obtained. The design features and optimal geometric parameters of the plasmatron have been determined: the inlet diameter is 3 mm, the outlet diameter is 2 mm.The design of the executive equipment has been developed and designed which implements the investigated process of generating droplets of the micro- and nanoscale range. A plasmatron nozzle was manufactured which forms the necessary directions of plasma flows for the formation of surface waves on the metal droplet surface under the influence of instabilities. An algorithm has been developed for controlling of executive equipment that implements the process of generating drops of micro- and nanoscale range.

Nucleation, first growth stages and structure of nano-sized polymer coatings deposited from active gas phase

This paper presents an analysis of the structural-morphological, kinetic patterns of the initial growth stages of single-component and composite (polymer-polymer and metal-polymer) nanoscale coatings based on the products of electron-beam dispersion of polymers. The main features of the deposition processes from the active gas phase occurring on the substrate surface and the established size dependences of the structure and molecular composition are explained on the basis of the adsorption-polymerization mechanism for the formation of coatings. It was established that among the most important features of the deposition process from the active gas phase is the simultaneous flow of polymerization and structure formation of adsorbed molecular fragments of the polymer under the conditions of exposure of the active components of the plasma, dispersive filler, and the substrate surface. This feature has a decisive influence on the nucleation of polymer particles, the molecular structure and morphology of nanoscale layers, as well as the dependence of their properties on thickness. Using the PTFE and PE coatings, it was shown that the orientation and ordering of the formed layers changes during the coating growth: at the initial stages of deposition in the layer up to 150 nm, the molecules are oriented predominantly parallel, and in thicker layers due to the bulk structure formation perpendicularly substrate surface. When deposited on the surface subjected to plasma treatment, the growth rate of the formed coating at the initial stages of growth increases by more than 5 times. At the same time, such layers contain predominantly linear molecules with a relatively lower molecular weight. The introduction of micro-and nanoscale polymer coatings in the process of their growth of the formed silver or copper nanoclusters leads to the formation of highly oriented, continuous, highly dispersed layers already at the initial stages of growth. The orientation of the macromolecules of the matrix with the maintenance of Ag or Cu nanoclusters in it has parameters characteristic of single-component coatings. In PTFE+Mo coatings, a linear dependence of molecular orientation on the layer thickness appears. In composite coatings containing silver nanoclusters, the effect of selective plasmon absorption was established.

Mathematical Modeling of Promising Structures of Metal Oxides

Information about the structure and properties of materials is especially important when working with micro-and nanoscale objects due to the complexity of obtaining it. This makes it relevant to use computer modeling to predict the required characteristics of materials. The electronic, magnetic, mechanical, and other properties of crystalline substances are determined by their structure: the periodicity of the lattice and the symmetry of the unit cell. This article discusses metal oxides with the general chemical formulas MeO (metals: Ca, Cd, Mg), MeO2 (metals: Hf, Ce, Zr), Me2O3 (metals: Er, Nd, Sc, Mn, Tl), and Me3O4 (using Fe as an example) and a crystal lattice with a cubic type of symmetry—structural types NaCl (rock salt), Fluorite, Bixbyite, and Spinel, respectively. The paper describes the model of ionic-atomic radii, which is widely used to model crystalline metal oxides. The application of the annealing simulation algorithm for calculating the metric parameters of the compounds under consideration is shown. The software implementation of the algorithm presented in this paper allows us to determine the coordinates of the atoms that are included in the elementary cell of the crystal lattice to calculate the lattice constant and the density of the packing of atoms in the crystal cell using the specified chemical formula and the space group symmetry. These structural characteristics can be used as the input parameters for determining the electronic, magnetic, and other properties. The article compares the values of lattice constants obtained as a result of modeling with experimental data.

Mathematical modeling of perspective structures of metal oxides

Information about the structure and properties of materials is especially important when working with micro-and nanoscale objects due to the high complexity of their obtaining. This makes it relevant to use computer modeling to predict the required characteristics of materials. Electronic, magnetic, mechanical, and other properties of crystalline substances are determined by their structure-the periodicity of the lattice and the symmetry of the unit cell. This article discusses metal oxides with the general chemical formulas MeO (metals: Ca, Cd, Mg), MeO2 (metals: Hf, Ce, Zr), Me2O3 (metals: Er, Nd, Sc, Mn, Tl) and Me3O4 (using Fe as an example) and a cubic symmetry type crystal lattice — structural types NaCl (rock salt), Fluorite, Bixbyite, Spinel accordingly. The paper describes the model of ion-atomic radii, which is widely used in the modeling of crystalline metal oxides. The application of the annealing simulation algorithm for calculating the metric parameters of the compounds under consideration is shown. The software implementation of the algorithm presented in this paper allows us to determine the coordinates of the atoms that are included in the elementary cell of the crystal lattice, calculate the lattice constant and the density of the packing of atoms in the crystal cell using the specified chemical formula and the space group symmetry. These structural characteristics can be used as input parameters for determining electronic, magnetic, and other properties. The article compares the values of lattice constants obtained as a result of modeling with experimental data.