The paper summarizes the basic principles of forming nanostructured composite materials to ensure high values of complex dielectric permittivity and the magnetic permeability in the microwave range based on multilayer carbon nanotubes (CNT), expanded graphite, graphene nanoplates (GNP), heterostructures, nanoferrites, conductive structures such as core-shell.
The concept of synthesis of a wide class of new nanostructures with high dielectric losses is formulated using methods of surface modification of polymer and highly dispersed oxides (SiO2, Al2O3, SnO2, TiO2) with copper iodide at concentrations that provide maximum manifestation of interfacial interaction on electrophysical properties.
It is shown that the values of ε 'and ε "on microwave range of composites polymer–CNT after CNT treatment by contactless grinding of materials exceed 2 times of initial CNTs, and the percolation threshold at low frequencies decreases more than 5 times and their bulk density decreases significantly.
A new method of synthesis of graphene nanoplates with adjustable dimensions by electrochemical oxidation of graphite electrodes in an alkaline electrolyte has been developed. The formation of GNP was confirmed by laser correlation spectroscopy, Raman spectroscopy, X-ray analysis and differential thermogravimetric analysis. The results of the electrical studies have shown that GNP have high values conductivity and polymer composites based on them have a low percolation threshold.
Physicochemical principles of formation of carbon-containing composites with iron, nickel, cobalt nanoparticles and their combinations are determined. NiCo nanoparticles on the surface of GNP, SiO2, CNT were obtained. TEM and X-ray diffraction methods show that the dimensions of the metal phases are 20-30 nm. The effective absorption of electromagnetic radiation in the microwave range of such composites is due to the natural ferromagnetic resonance of nanoscale metal structures.
Synthesized CuS/CdS, Cu2S/CdS heterostructures based on CdS nanofibers with core-shell morphology and aspect number ~ 10. It is established that the percolation threshold for Cu2S/CdS–polyvinylidenefluoride (PVDF) and CuS/CdS–PVDF systems is 0.05 volume fraction. The Cu2S/CdS–PVDF system is characterized by a more ordered crystalline structure and has higher electrophysical parameters on the microwave.
The electrophysical properties of new magnetic nanomaterials and nanocomposites with high dielectric and magnetic losses in the microwave range of electromagnetic radiation and for the creation of absorbing materials, media, coatings have been developed, synthesized and investigated.
Key words: microwave range, heterostructures, percolation threshold, clusters, dielectric permittivity and the magnetic permeability, polymer, nanostructured composites, interfacial surface, carbon nanotubes.
