Recently, designers of electronic equipment have paid special attention to the issue of electromagnetic compatibility (EMC) of devices with their own components and assemblies. This is due to the high sensitivity of semiconductor microcircuits to electromagnetic interference. This interference can be caused either by natural phenomena, such as lightning strikes, or by technical processes, such as transients in circuits during fast periodic or random switching. Either way, interference implies a sudden change in voltage or current in a circuit, which is undesirable, whether it propagates along a cable or is transmitted as an electromagnetic wave. The purpose of this article is to review the works devoted to the development, creation, and investigation of modern polymeric nanocomposite materials used for shielding electromagnetic radiation and their effective application for solving problems of electromagnetic compatibility. Additionally, the approach to design EMI shielding complex media with predetermined parameters based on investigation of various properties of possible components is shown. In the review, all polymer composites are classified according to the type of filler. The issues of the interaction of a polymer with conductive fillers, the influence of the concentration of fillers and their location inside the matrix, and the structure of the nanocomposite on the mechanisms of electromagnetic interaction are considered. Particular attention is paid to a new generation of nanocomposite materials with widely adjustable electrical and magnetic properties. A wide class of modern filled polymeric materials with dielectric and magneto-dielectric losses is considered. These materials make it possible to create effective absorbers of electromagnetic waves that provide a low level of reflection coefficient in the microwave range. The model mechanisms for shielding electromagnetic radiation are considered in the paper. A detailed review of the electro-physical properties of polymer nanocomposites is provided. Multilayer electrodynamic media containing combinations of layers of filled polymer composite materials with nanoparticles of different compositions and manufactured using a single technology will make it possible to create electrodynamic media and coatings with the required electro-physical characteristics of absorption, transmission, and reflection. Within the framework of the two-layer coating model, the difference in the effects of the interaction of electromagnetic radiation with conductive layers located on a dielectric and metal substrate is demonstrated. It is shown that in order to achieve optimal (maximum) values of reflection and absorption of electromagnetic radiation in the appropriate frequency range, it is necessary to fit the appropriate layer thicknesses, specific conductivity, and permittivity. Such approach allows designers to create new shielding materials that can effectively vary the shielding, absorbing, and matching characteristics of coatings over a wide frequency band. In general, it can be said that the development of innovative polymer composite materials for shielding electronic devices from electromagnetic interference and excessive electromagnetic background is still an important task. Its solution will ensure the safe and uninterrupted operation of modern digital electronics and can be used for other applications.

Composite nanomaterials have been prepared through thermal decomposition of palladium diacetate. The composite contains palladium nanoparticles embedded in high-pressure polyethylene. The materials were studied by a number of different physico-chemical methods, such as transmission electron microscopy, X-ray diffraction, X-ray absorption spectroscopy, electron paramagnetic resonance, and EXAFS. The average size of the nanoparticles is 7.0 ± 0.5 nm. It is shown that with the decrease of metal content in the polymer matrix the average size of nanoparticles decreased from 7 to 6 nm, and the coordination number of palladium also decreased from 7 to 5.7. The mean size of palladium particles increases with the growing concentration of palladium content in the matrix. It is shown that the electrophysical properties of the material obtained depend on the filler concentration. The chemical composition of palladium components includes metallic palladium, palladium (III) oxide, and palladium dioxide. All samples have narrow lines (3–5 Oe) with a g factor of around two in the electron paramagnetic resonance (EPR) spectra. It is shown that EPR lines have uneven boarding by saturation lines investigation. The relaxation component properties are different for spectral components. It leads to the spectrum line width depending on the magnetic field value. At first approximation, the EPR spectra can be described as a sum of two Lorentzian function graphs, corresponding to the following two paramagnetic centers: one is on the surface, and one is inside the palladium particles. Some of the experimental characteristics were measured for the first time. The data obtained indicate interesting properties of palladium-based nanocomposites, which will be useful for obtaining products based on these materials.

Bi₂O₃ was investigated in the role of a modifier for BaTiO₃ powder synthesized in a water vapor atmosphere at 200 °C and 1.55 MPa. Modification was aimed at increasing the sinterability of the powder as well as improving the structural and dielectric properties of the obtained ceramics. The morphology and phase contents of the synthesized BaTiO₃ powder were controlled by the methods of SEM and XRD. Properties of pure and Bi-doped BaTiO₃ ceramics were comprehensively studied by XRD, SEM, dielectric spectroscopy, and standard approaches for density and mechanical strength determination. Doping with Bi₂O₃ favored BaTiO₃ ceramic densification and strengthening. The room-temperature dielectric constant and the loss tangent of Bi-doped BaTiO₃ were shown to stabilize within the frequency range of 20 Hz to 2 MHz compared to non-doped material. The drop of dielectric constant between room temperature and Curie point was significantly reduced after Bi₂O₃ addition to BaTiO₃. Bi₂O₃ appeared to be an effective modifier for BaTiO₃ ceramics produced from non-stoichiometric powder synthesized in water vapor.

To control the physical properties of polar and nonpolar liquid media, the parameters of model systems based on paraffin and silicone oils, as well as glycerin, were measured using electrophysical and acoustoelectric methods. Electrophysical studies were performed with an Agilent E4980A LCR meter and a measuring cell consisting of an Eppendorf tube and two coaxial nickel electrodes forming a cylindrical capacitor. The permittivity of the liquid was determined from the formula for the capacitor. For the acoustic part of the problem, ST,X-quartz was used as the piezoelectric plate, on which a fluoroplastic cell for liquid was placed. The measurements were carried out in three stages: measurement of the phase and amplitude of the acoustic wave (i) without contact with the liquid, (ii) in contact with a pure test liquid, and (iii) in contact with the test liquid with a filler. Microparticles of pharmaceutical activated carbon and the surfactant sorbitan monooleate were used as fillers. The viscosity of the suspensions was determined from the difference between the attenuation of an acoustic wave in the presence of the pure liquid and liquid with filler.

Composite materials based on NiFe₂O₄ nanoparticles and polyethylene matrix have been synthesized by thermal decomposition to expand the application area of high-pressure polyethylene by filling it with nanoscale particles. The synthesized compositions were obtained in the form of a dark gray powder and compressed for further study According to TEM, the average particle size in composites was 2, 3, and 4 nm in samples with a filling of 10%, 20% and 30%. The concentration dependences of the specific electrical resistivity ρ_V, dielectric permittivity ε, saturation magnetization M_S and the parameters of reflection and attenuation of microwave power of the obtained composites were investigated. The threshold for percolation in such materials is found to be within a concentration range of 20…30%. The electronic and atomic structure of composites was studied by methods of Mössbauer spectroscopy, X-ray diffraction and X-ray absorption spectroscopy. The closest atomic environment of nickel and iron in nanoparticles is close to that of crystalline NiFe₂O₄. The dependence of the nanoparticles size as well as the dependence of the number of tetrahedral or octahedral iron positions in nickel ferrite nanoparticles to their content in polyethylene matrix is established. It is shown that composite materials based on NiFe₂O₄ nanoparticles and polyethylene matrix can be used as components of electromagnetic compatibility systems.

To control the physical properties of polar and nonpolar liquid media, the parameters of model systems based on paraffin and silicone oils, as well as glycerin, were measured using electrophysical and acoustoelectric methods. Electrophysical studies were performed with an Agilent E4980A LCR meter and a measuring cell consisting of an Eppendorf tube and two coaxial nickel electrodes forming a cylindrical capacitor. The permittivity of the liquid was determined from the formula for the capacitor. For the acoustic part of the problem, ST,X-quartz was used as the piezoelectric plate, on which a fluoroplastic cell for liquid was placed. The measurements were carried out in three stages: measurement of the phase and amplitude of the acoustic wave (i) without contact with the liquid, (ii) in contact with a pure test liquid, and (iii) in contact with the test liquid with a filler. Microparticles of pharmaceutical activated carbon and the surfactant sorbitan monooleate were used as fillers. The viscosity of the suspensions was determined from the difference between the attenuation of an acoustic wave in the presence of the pure liquid and liquid with filler.