Polymer composite materials based on CuS/ CdS, Cu 2 S/CdS and Ag 2 S/CdS were obtained by substitution of Cd with Ag, Cu (II) and Cu (I) ions in the CdS rodlike nanocrystalline and investigated their electrophysical properties. It was found that the electrical conductivity of CuS/CdS heterostructure is in five orders higher compared to the CdS. It was shown that the values of the complex permittivity at identical content of CuS and Cu 2 S nanoparticles are more than 40 % higher for the 0.3 Cu 2 S/CdS-PVDF system in comparison with the 0.3 CuS/CdS-PVDF.
Nanosize nickel ferrite was synthesized by the sol-gel autocombustion method. The surface of nickel ferrite was modified by copper sulphide with the volume fractions from 0.2 to 0.42. For the CuS/NiFe2O4 composites the values of complex permittivity and permeability in the microwave range, values of conductivity at low frequencies and magnetic characteristics were investigated. Polymer composites CuS/NiFe2O4-polychlorotrifluoroethylene (PCTFE) were obtained by hot pressing technique. With an increase in the content of copper sulphide of polymer composites, an increase in the values of the complex dielectric constant in the microwave range of 2-3 times was observed. The values of electrical conductivity for the 0.2CuS/NiFe2O4-PCTFE system are 4-5 orders of magnitude lower than for the 0.42CuS/NiFe2O4-PCTFE system with an increase in the concentration of copper sulphide in polymer composites. The change in the ratio of the conducting and magnetic components in the studied system makes it possible composites with adjustable permittivity and permeability in the microwave range.
The creation of new nanomaterials for absorbtion of electromagnetic radiation microwave range is an important direction in consequence of electromagnetic pollution of the environment. The aim of the paper was to develop and synthesize the polymer-filled systems based on the polychlorotrifluoroethylene and tin dioxide modified by nickel ferrite in order to study their electrophysical properties as potential materials absorbing electromagnetic radiation. NiFe2O4/SnO2 nanocomposites with a volume content of nickel ferrite on the surface of tin dioxide from 0.62 to 0.8 were synthesized by co-precipitation. Size of SnO2 and NiFe2O4 nanoparticles was determined by a transmission electron microscope and its about 30–50 nm and 15–30 nm, respectively. For the NiFe2O4/SnO2 nanocomposites the values of complex permittivity and complex permeability in the microwave range, values of conductivity at low frequencies were investigated. Maximum values of complex permittivity and complex permeability were found for NiFe2O4/SnO2 nanocomposites at the volume content of nickel ferrite 0.62. An increase was observed in the complex permittivity for the NiFe2O4/SnO2–polychlorotrifluoroethylene system, 2–3 times greater than the values related to the NiFe2O4/SnO2 nanocomposites. The electrical conductivity at low frequencies (100 Hz) of polymer composites increases by an order of magnitude with a decrease of the concentration of nickel ferrite on the surface of tin dioxide. It was found that the calculated absorption coefficient of an electromagnetic wave in the frequency range 1–41 GHz for NiFe2O4/SnO2 nanocomposites is about 2 times greater than that for nickel ferrite. It is shown that the creation of nanocomposites based on a conductive component modified by a magnetic component is more efficient for the processes of absorption of electromagnetic waves in the microwave range at optimal ratios of the values of the permittivity and permeability than pure ferrite.
In order to synthesize the polymer composite system of the PCTFE-CuS/ZnS, the nanodispersed ZnS was synthesized by hydrothermal method afterwards heterostructures of CuS/ZnS were obtained using ion-substitution mechanism. The concentration dependence of the real and the imaginary components of the complex dielectric permeability and electrical conductivity of synthesized samples were investigated. Obtained composites have high values of the dielectric permeability at high frequencies and conductivity at low frequencies. At 50 % (molar) substitution of Zn ions by Cu the percolation threshold was determined at the volumetric content of CuS about 0.06.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.