Transparent conductive electrodes that combine flexibility with effective electromagnetic interference (EMI) shielding are important for next-gen flexible electronics and 5G/6G communication devices. Achieving high optical transparency, low sheet resistance, and broadband shielding performance remains a sophisticated task. This work demonstrates a solution: the synthesis and comprehensive characterization of flexible In2O3/Ag/In2O3 (IAI) structures on polyethylene terephthalate substrates. The optimized structure with a 13.2 ± 1.1 nm silver interlayer achieves an incredible combination of properties: high optical transmittance (82.59% at 500 nm), low sheet resistance (6.4 ± 0.8 Ω/sq), and insignificant optical haze (1.04%). Broadband EMI shielding measurements from 10 MHz to 1 THz reveal a uniform shielding effectiveness of 25–30 dB across band from radiowave to terahertz. The IAI structures also show outstanding mechanical resilience, maintaining their electrical and shielding performance under repeated bending. This unique set of attributes positions IAI thin films as a prospective material for transparent EMI shielding in advanced telecommunications and flexible optoelectronics.

In this study flexible polymer nanocomposite material with different types of carbon nanotubes (CNTs) (single-walled CNT [SWCNT] or multi-walled CNT [MWCNT]) has been obtained for use in stretchable elements of flexible structures. The features of electrically conductive nanostructures and their distribution in the nanocomposite material have been studied using Raman spectrometer and scanning electron microscope, respectively. Setup for studying the functional characteristics of the nanocomposite material based on a testing machine has been developed. The setup ensures simultaneous measurement of the electrical resistance of the nanocomposite material under cyclic tension. The ultimate tensile strength of the polymer composite under 25% tension with different electrically conductive nanostructures has been determined. It has been exposed for a sample with MWCNT, the ultimate tensile strength is significantly lower. It has been revealed that the highest tensile strength had been achieved in composites at about 0.37 MPa. The strain sensitivity (gauge factor [GF]) of polydimethylsiloxane (PDMS)/MWCNT has higher GF value compared to PDMS/SWCNT. This shows a higher potential for using them as fillers for creating sensor systems based on nanocomposite conductive materials.

The modern pace of scientific and technological development dictates unprecedented requirements for the speed of information transfer. The THz range is considered one of the most promising and has been actively developing in recent years. Along with the need to develop transmitting devices, the demand for shielding materials in this range, including transparent ones, is also growing. In this work, we present two types of composite films based on silver nanowires and PEDOT:PSS. We characterized these composite films in terms of optoelectrical parameters, as well as shielding characteristics in the THz range. We found that our composite films have a sheet resistance (R□) of about 8.6 ± 1.2 Ω/□ with a transparency of about 83.41 % and shielding efficiency is 25.85 dB in the THz region, which makes them excellent candidates for transparent shielding materials. We also made a bilayer sandwich structure from these composite films, which showed a shielding efficiency of about 49.34 dB in the range of 0.2–0.8 THz with a transparency of 66.33%. In addition, we assessed the possibility of real application of the structures in terms of stability to external conditions. Our composite films sustain atmospheric corrosion and maintain stable sheet resistance for 30 days.

Highly efficient shielding materials, transparent in the visible and IR ranges are becoming important in practice. This stimulates the development of cheap methods for creating transparent conductors with low sheet resistance and high optical transparency. This work presents a complex approach based on preliminary modeling of the shielding characteristics of two-layer sandwich structures based on irregular aluminum mesh (IAM) formed by the cracked template method. Experimentally measured spectral dependences of the transmission coefficient of single-layer IAM are used as a reference point for modeling. According to the simulation results, two types of sandwich structures were designed using IAM, with varying filling factors and a fixed PMMA layer thickness of 4 mm. The experimentally measured shielding characteristics of the sandwich structures in the range of 0.01-7 GHz are in good agreement with the calculated data. The obtained structures demonstrate a shielding efficiency of 55.96 dB and 65.55 dB at a frequency of 3.5 GHz (the average range of 5G communications). At the same time, their optical transparency at a wavelength of 550 nm are 84.07% and 75.78%, respectively. Our sandwich structures show electromagnetic shielding performance and uniform diffraction pattern. It gives them an advantage over structures based on regular meshes. The obtained results highlight the prospect of the proposed comprehensive approach for obtaining highly efficient, low-cost optically transparent shielding structures. Such materials are needed for modern wireless communication systems and metrology applications.

Electrically conductive nanoporous membranes represent a class of stimuli-responsive materials, which selectivity/permeability characteristics can be adjusted by varying the surface potential. In this work, we perform a comprehensive theoretical and experimental study of ionic conductivity of such membranes. The 2D Space charge and 1D Uniform potential models are used to describe the ion transport through a cylindrical nanopore. The calculations show that the imposed electric field polarizes the conductive surface, which results in the continuous variation of electronic surface charge from positive to negative along the nanopore. A higher concentration of cations (anions) is observed at negatively (positively) charged part of the nanopore. The increase of charge carries concentration due to polarization effect results in the enhancement of ionic conductivity with increasing the voltage difference. The corresponding current-voltage curves are non-linear. The enhancement can reach a few orders of magnitude at low salt concentrations, but becomes much smaller at high concentrations. The presence of chemical charge has a screening effect on the interaction of electric field with the electronic charge on the nanopore surface, and reduces the conductivity enhancement. A novel analytical solution is derived for the dependence of ionic current on the Stern layer capacitance, salt concentration, and the applied potential difference. The theoretical predictions are first confirmed by the ionic conductivity measurements in porous anodic alumina membranes with carbon nanotubes inside the pores. The experimental data are approximated by the 1D Uniform potential model curves using chemical charge as a fitting parameter. Strong enhancement of ionic conductivity (more than 6 times) and the corresponding nonlinear dependence of current on the applied voltage is experimentally registered at low KCl concentrations (0.1 - 10 mM) with increasing the voltage difference.

Nowadays, the Internet of Things (IOT), electronics, and neural interfaces are becoming an integral part of our life. These technologies place unprecedentedly high demands on materials in terms of their mechanical and electrical properties. There are several strategies for forming conductive layers in such composites, e.g., volume blending to achieve a percolation threshold, inkjet printing, lithography, and laser processing. The latter is a low-cost, environmentally friendly, scalable way to produce composites. In our work, we synthesized AgNW and characterized them using Ultraviolet-visible spectroscopy (UV-vis), Transmission electron microscopy (TEM), and Selective area electron diffraction (SAED). We found that our AgNW absorbed in the UV-vis range of 345 to 410 nm. This is due to the plasmon resonance phenomenon of AgNW. Then, we applied the dispersion of AgNW on the surface of the polymer substrate, dried them and we got the films of AgNW.. We irradiated these films with a 432 nm laser. As a result of the treatment, we observed two processes. The first one was the sintering and partial melting of nanowires under the influence of laser radiation, as a consequence of which, the sheet resistance dropped more than twice. The second was the melting of the polymer at the interface and the subsequent integration of AgNW into the substrate. This allowed us to improve the adhesion from 0–1 B to 5 B, and to obtain a composite capable of bending, with radius of 0.5 mm. We also evaluated the shielding efficiency of the obtained composites. The shielding efficiency for 500–600 nm thick porous film samples were 40 dB, and for 3.1–4.1 µm porous films the shielding efficiency was about 85–90 dB in a frequency range of 0.01–40 GHz. The data obtained by us are the basis for producing flexible electronic components based on AgNW/PET composite for various applications using laser processing methods.

Developing new environmentally friendly methods of producing materials for electronics is critical important task for material science. Manufacturing process of semiconductor materials, transparent electrodes, electrical and thermal conductive pastes, fillers for conductive inks and some other materials should be improved from environmental point of view. Here we present a waste-free closed cycle fabrication of two important materials for electronics based on the concept of a self-organized cracked template. Optically transparent silver meshes and silver microflakes were obtained in waste-free manufacturing cycle. The morphological, structural, optoelectric, and shielding properties of transparent silver meshes and silver microflakes films were studied in detail. Also, we made transparent heater in close manufacturing cycle. The first type of materials are transparent silver meshes with irregular structure that have a transparency of more than 80

In this work, nanocomposite photoelectrodes of the TiO2/ Au composition were manufactured, in which the size of plasmonic Au nanoparticles was varied, and the morphology of the TiO2 layer, depending on the thickness, changed from an island to a continuous layer. The influence of the morphology of plasmonic Au nanoparticles and the TiO2 layer on the optical and photoelectrochemical characteristics of hybrid photoelectrodes was studied. It has been shown that continuous coating of Au nanoparticles with a TiO2 layer (layer thickness 10 and 15 nm) leads to a decrease in the photoelectric response, and the decrease in photocurrent density and photoconversion efficiency decreases in proportion to the thickness of the TiO2 layer. The indicated drop in characteristics when plasmonic particles are located under the TiO2 layer is presumably associated with the scattering and recombination of charge carriers in the semiconductor layer. The best performance was shown by a system in which large Au nanoparticles (10 nm) are coated with a 5 nm thick layer of titanium dioxide; in this geometry, Au nanoparticles are decorated with TiO2 nanoparticles, as a result of which the photoelectrode-electrolyte interface has a more complex structure.

The problem of sputtering of thick metal films on micro and nanotemplates is important for obtaining mesh transparent conductors with excellent optoelectric characteristics. In this work, we demonstrate for the first time the possibility of controlling the degree of peeling of the cell perimeter from the substrate for a cracked template based on egg white by alternating the operations of moistening the template with saturated water vapor and shock drying with hot air. Local peeling of the cracked template cells perimeter makes it possible to increase the thickness of the metal sputtered on the cracked template by more than 1 mu m, which is not achievable for other lithographic approaches. Our technique was used to obtain thick Ag meshes with a low sheet resistance of no more than 1.59 omega/sq and a transparency of about 89.1%. The thick Ag meshes show a shielding efficiency (SE) of 49 dB or 99.998% of the incident power of an electromagnetic wave at a frequency of 1 GHz. In a sandwich geometry, thick Ag meshes, which simulates a real shielding window, the shielding efficiency (SE) reaches 71 dB with a transparency of more than 80%.

The study of ruthenium catalysts for ammonia decomposition on carbonized and non -carbonized Al2O3 nanofibers (ANF) showed that the activity of catalysts with carbonized supports (ANFC) was 2-3 times higher compared to non-carbonized ones. Thus, on Ru/ ANFC and Ru/ANF the release of hydrogen reached 133.5 and 34.7 mmol H2/(min & BULL;gcat), respectively, whereas on Ru-BaAc/ANFC and Ru-BaAc/ANF, only 118.8 and 58.6 mmol H2/ (min & BULL;gcat), respectively. On the average, the activation energy of ammonia decomposition on ANFC-supported catalysts is 15 kJ/mol lower than that value for ANF-supported cata-lysts. According to TEM data, Ru particles on ANFC are larger than on ANF, but are more evenly distributed. An increase in the activity of the catalyst correlates with a change in the electronic state of the active component. XPS data for Ru indicate a shift in the binding energy towards lower values when going from ANF to ANFC.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

This work presents first-of-its kind research on the effect of alumina nanofibers (ANF) on drilling emulsions. ANF is a new generation crystalline nanofiber material with ultra-high mechanical strength and stability. From a physicochemical point of view, the material constitutes alumina nanofibers with a unidirectional dispersed structure and a faceted surface. Such characteristics provide ANF with a wide range of possibilities for interacting with various polymer matrices, as well as with ceramic and metallic materials. A number of characteristics and properties, such as viscosity, rheology, structure formation, filtration and antifriction properties, clay swelling kinetics, and stability of oil-based drilling fluids (OBDF) modified with aluminum oxide nanofibers, have been studied. These studies have demonstrated the positive effect of nanofibers on all functional characteristics of drilling fluids. It was found that nanofibers significantly change the rheological characteristics, reduce filtration losses, and reduce the coefficient of friction of drilling fluids without significantly degrading their colloidal stability in the concentration range not exceeding 1 wt%. The addition of ANF doubles the effective viscosity and yield strength, reduces filtration losses by a factor of 2.5, reduces the coefficient of friction by almost two times, and does not impair the colloidal and thermal stability of oil-based drilling fluids. This paves the way for the use of this material as the most promising one in drilling fluid development.

This paper considers the photoelectrochemical characteristics of a composite porous TiO2 thin film with deposited plasmonic gold nanoparticles. The deposition of gold nanoparticles was carried out by the laser-induced chemical liquid-phase deposition (LCLD) method. The structural characteristics of the composite have been studied; it has been shown that the porous TiO2 film has a lattice related to the tetragonal system and is in the anatase phase. Gold nanoparticles form on the surface of a porous TiO2 film. A complex of photoelectrochemical measurements was carried out. It was shown that the deposition of plasmonic gold nanoparticles led to a significant increase in the photocurrent density by ~820%. The proposed concept is aimed at testing the method of forming a uniform layer of plasmonic gold nanoparticles on a porous TiO2 film, studying their photocatalytic properties for further scaling, and obtaining large area Au/TiO2/FTO photoelectrodes, including in the roll-to-roll process.

The article "Experiment to create a radio communication channel in the marine environment" (authors: A.K. Tomilin, A.F. Lukin, A.N. Gulkov) published in Journal "Technical Physics Letters" (2021, vol. 47, Issue 11) is analyzed from the standpoint of classical physics. The organization of the experiment in the mentioned publication, interpretation of its results, and theory underlying the work are criticized. The proposed material is a methodological commentary and is intended to form consistent approaches to be used in studying and interpreting further works on creation of radio communication channels. Keywords: Radio communication in the marine environment, electromagnetic waves, methodological notes

The study of ruthenium catalysts for ammonia decomposition on carbonized and noncarbonized Al2O3 nanofibers (ANF) showed that activity of the catalysts with carbonized supports (ANFC) was twofold higher as compared to noncarbonized ones. Thus, on Ru/ANFC and Ru-Cs/ANFC the release of hydrogen reached 8.7 and 18.3 mmol H-2/(min.g(cat)), respectively, whereas on Ru/ANF and Ru-Cs/ANF, only 4.4 and 9.6 mmol H-2/(min.g(cat)), respectively. According to TEM, Ru particles on ANFC have a greater size than on ANF but are distributed more uniformly. As shown by TEM, XRD and XPS data, ANFC and ANF fibers are strongly different.

The paper deals with the production and study of nanocomposite powder paints based on alumina nanofibers. For nanodispersed fillers, the nature of the surface states on the filler particles is important. The problem of introducing nanomaterials into a polymer matrix cannot provide an effective solution without matching the surface states of the nanomaterial filler and the polymer matrix for the resulting composite materials. The consistency of the surface states of the nanomaterial filler and the polymer matrix determines the quality of transfer of the necessary properties to the resulting polymer composite. In order to increase the affinity of alumina nanofibers with a matrix of powder paint, the nanofibers were treated with 3-glycidyloxypropyltrimethoxysilane (GLYMO) in toluene. It is shown in the work that the addition of alumina nanofibers leads to a hardening of the coating, an increase in its elasticity, and an increase in corrosion resistance. Finishing of alumina nanofibers in a solution of silane in toluene leads to its functionalization, which is sufficient for the distribution of nanofibers in the polymer matrix of the paint and improvement of its operational properties.

Embedded copper mesh coatings with low sheet resistance and high transparency were formed using a low-cost Cu seed mesh obtained with a magnetron sputtering on a cracked template, and subsequent operations electroplating and embedding in a photocurable resin layer. The influence of the mesh size on the optoelectric characteristics and the electromagnetic shielding efficiency in a wide frequency range is considered. In optimizing the coating properties, a shielding efficiency of 49.38 dB at a frequency of 1 GHz, with integral optical transparency in the visible range of 84.3%, was obtained. Embedded Cu meshes have been shown to be highly bending stable and have excellent adhesion strength. The combination of properties and economic costs for the formation of coatings indicates their high prospects for practical use in shielding transparent objects, such as windows and computer monitors.

To find out whether Al2O3 nanofiller is effective in improving the characteristics of polymer composites, composite polymer films based on biodegradable polylactide and epoxidized aluminum oxide nanofibers were obtained by solution casting. Surface morphology, mechanical and thermal properties of composites were studied by SEM, IR-Fourier spectroscopy, DSC and DMA. It was shown that, below and above the percolation threshold, the properties of the films differ significantly. The inclusion of alumina nanoparticles up to 0.2% leads to a plasticizing effect, a decrease in the crystallization temperature and the melting enthalpy and an increase in the tensile stress. An increase in the content of alumina nanoparticles in films above the percolation threshold (0.5%) leads to a decrease in the crystallinity of the films, an increase in stiffness and a drop in elasticity. Finding the percolation threshold of alumina nanoparticles in PLA films makes it possible to control their properties and create materials for various applications. The results of this study may have major significance for the commercial use of aluminum oxide nanofibers and can broaden the research field of composites.

Samples of two-layer ceramics based on polydisperse powder of the pearlite mineral and foam silicates possessing high compressive strength up to 50 MPa, thermal stability up to 1150°C, and water permeability of 272 m3/h m2 bar have been obtained. According to the X-ray powder diffraction analysis, the supporting substrate material is X-ray amorphous. The average pore size of the supporting substrate is 40 µm, while the average pore size of the modifying layer is 17 µm according to the bubble method and electron microscopy. The obtained materials are promising for use as substrates of microfiltration, ultrafiltration, and nanofiltration membranes.

We have studied the rheological properties of colloidal suspensions based alumina nanofibers (ANF) with a mass fraction of 0.125-2 wt%. The ANFs used in this work are stand out by a high aspect ratio L/D 106- 107 (dry ANF before dispersion) and ease of dispersion due to the self-organized aligned structure of ANF, which is characteristic of our synthesis method. It was shown that ANF suspensions are characterized by high colloidal stability, zeta potential has a significant dependence on ANF volume fraction. ANF have a strong effect on the shear viscosity of colloidal suspensions; non-Newtonian behavior is observed in suspensions with an ANF mass fraction of 0.5 wt%. A comprehensive study of the propagation of ultrasound in ANF suspensions was carried out. Based on experimental results on the scattering of ultrasound in suspensions and theoretical calculations, data on the bulk viscosity of ANF suspensions were obtained for the first time. The results of the study allow us to judge the possibility of using ANF as a promising fibrous additive to optimize the rheological properties of suspensions for various technical purposes, which include drilling muds, paint and varnish compositions, concrete-cement mixtures. (c) 2022 Elsevier B.V. All rights reserved.