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Nanocomposites containing components with semiconductor, ferroelectric, and ferromagnetic properties have attracted considerable attention of specialists due to the range of possible applications, including catalysis and electrocatalysis, electrode materials for solar and fuel cells, capacitors, electrical and biosensors, anti-corrosion coatings and much more. In recent years, both fundamental and applied interest in this direction of research is due to the possibility of creating a new type of controlled microwave devices and tools. The aim of the work is to develop methods for the synthesis of nanostructured NiCo composites based on BaTiO3 and TiO2, as well as to find the differences and regularities of their physicochemical properties. Two series of samples with different content of NiCo nanoparticles based on titanium oxide (TiO2) and barium titanate (BaTiO3) were obtained. NiCo particles were obtained by the method of chemical precipitation of nickel and cobalt carbonates in equal parts from a hydrazine hydrate solution at the temperature of 350 K. The results of X-ray phase analysis indicate the chemical purity of the obtained samples. The values of ε′, ε″ at a frequency of 9 GHz for the NiCo/BaTiO3 system are twice as high compared to NiCo/TiO2 for the corresponding values of the NiCo content, which is due to the higher values of ε′, ε″ of the initial barium titanate. Electrical conductivity of NiCo/BaTiO3 system changes by six orders of magnitude, which indicates the formation of a continuous percolation cluster of metal particles on the surface of dielectric BaTiO3 particles. The composites are heat-resistant up to 630K, as shown by the method of thermogravimetry and pronounced magnetic properties. The program for calculating frequency dependences of reflection and absorption coefficients in a complex form has been developed. EMF absorption for composites from the radiation frequency and the position of the minima of these characteristics, which agree satisfactorily with the experiment. The obtained composites can be promising components for obtaining composite systems and paints for protection against electromagnetic radiation. [ABSTRACT FROM AUTHOR]

The processes of carbonization of sucrose-containing coatings on the surface of single-domain magnetite and magnetosensitive nanocomposite (MNC) Fe3O4/Al2O3 are studied. The MNC with a carbon surface is synthesized by the method of low-temperature pyrolysis of carbohydrates. As revealed, the used heat-treatment mode does not lead to deterioration of the magnetic characteristics of magnetite under the condition of preliminary creation of a protective layer of alumina on its surface. Differential thermal analysis (DTA) in combination with differential thermogravimetric analysis (DTGA) and programmed temperature-desorption mass spectrometry show that the carbonization of sucrose under these conditions is complete. The shape and dimensions of the Fe3O4, Fe3O4/Al2O3 and Fe3O4/Al2O3/С MNCs are investigated by the TEM method. As established, the values of the specific saturation magnetization of MNCs are consistent with the corresponding changes in the mass fraction of magnetite in the Fe3O4/Al2O3 and Fe3O4/Al2O3/С structures. The results of TEM studies and magnetic measurements indicate the formation of the Fe3O4/Al2O3 and Fe3O4/Al2O3/С MNCs by the core–shell type. Methylene blue is used to study the adsorption activity of the Fe3O4/Al2O3/С MNC surface. The results of the work can be used in the development of new magnetically controlled adsorption materials for medical–biological purposes. [ABSTRACT FROM AUTHOR]

One of the most widely used antitumor chemotherapeutic drugs is “Cisplatin” (active substance - cis - diaminodichloroplatinum), the side effects of which are the cumulative ototoxic, nephrotoxic and neurotoxic effects. The use of drug carrier systems for targeted delivery and adsorbents for extraction, in particular magnetite-carbon nanocomposites, will minimize unwanted toxic effects without reducing the therapeutic effect of cisplatin. For this purpose, a nanocomposite (NCs) of Fe3O4/Al2O3/С with a carbon surface was synthesized, where a layer of alumina protects magnetite during the pyrolysis of carbohydrates. The synthesized samples were characterized by TEM, XRD, mass spectrometry methods, magnetic properties and specific surface area were studied. It has been found that the used heat treatment mode (T = 500 °С, argon medium) is sufficient for complete carbonization of sucrose and preserves the phase of magnetite which does not lead to deterioration of magnetic characteristics. The results of TEM studies and magnetic measurements indicate the formation of the Fe3O4/Al2O3/С nanocomposite of the core-shell type. The adsorption of Cisplatin on the surface of NCs Fe3O4/Al2O3/С was performed and the adsorption process dependent on the contact time, pH of the solution and cisplatin concentration was studied. The experimental results of kinetic studies were analyzed for compliance with the theoretical models of Boyd and Morris-Weber, models of pseudo-first and pseudo-second orders. Langmuir and Freundlich isotherm models were used to model adsorption processes. The limiting factor of adsorption is the external diffusion mass transfer processes, which correlates with the calculated parameters of the pseudo-first-order model (r² = 0.985). The correlation of theoretical and practically obtained values of adsorption capacity indicates the possibility of using the Freundlich model to describe the adsorption of Cisplatin on the surface of Fe3O4/Al2O3/C. [ABSTRACT FROM AUTHOR]

Copyright of Chemistry, Physics & Technology of Surface / Khimiya, Fizyka ta Tekhnologiya Poverhni is the property of National Academy of Sciences of Ukraine, Chuiko Institute of Surface Chemistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chemistry, Physics & Technology of Surface / Khimiya, Fizyka ta Tekhnologiya Poverhni is the property of National Academy of Sciences of Ukraine, Chuiko Institute of Surface Chemistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The synthesis has been made of patterns of single-domain magnetite and related nanocomposites: Fe3O4/dimercaptosuccinic acid, Fe3O4/hydroksylapatite, Fe3O4/γ-aminopropylsiloxane. The influence has been examined of chemical nature of surface of the synthesized nanostructures on the adsorption of cis-dichlorodiamineplatinum complexes. The isotherms and kinetics of adsorption were studied in terms of Pt2+ cations. The best adsorption parameters were observed for Fe3O4/polyacrylamide and Fe3O4/γ?-aminopropylsiloxane nanocomposites. The perspective of using nano-sized magnetite and its modified forms has been shown for the creation of magnetosensitive adsorbents of cis-dichloro-diamineplatinum complexes, in particular, for biomedical applications. [ABSTRACT FROM AUTHOR]

Research work results are reviewed related to the problem on directed transport of drugs as well as the current status and prospects in this field. The ways have been analyzed of nanocomposites creation with multilevel hierarchical architecture and functions of biomedical nanorobots such as the capability of microbiological objects recognition in biological media, directed transport and deposition of drugs in target organs, diagnosis and treatment of diseases at the cellular level. Physico-chemical, medical, and biological research data confirm effectiveness of such nanocomposites usage for the creation of new therapeutic forms of combined cytotoxic, immunotherapeutic, hyperthermic effect as well as for neutron capture therapy. [ABSTRACT FROM AUTHOR]

Nanocomposites containing components with semiconductor, ferroelectric, and ferromagnetic properties have attracted considerable attention of specialists due to the range of possible applications, including catalysis and electrocatalysis, electrode materials for solar and fuel cells, capacitors, electrical and biosensors, anti-corrosion coatings and much more. In recent years, both fundamental and applied interest in this direction of research is due to the possibility of creating a new type of controlled microwave devices and tools. The aim of the work is to develop methods for the synthesis of nanostructured NiCo composites based on BaTiO3 and TiO2, as well as to find the differences and regularities of their physicochemical properties. Two series of samples with different content of NiCo nanoparticles based on titanium oxide (TiO2) and barium titanate (BaTiO3) were obtained. NiCo particles were obtained by the method of chemical precipitation of nickel and cobalt carbonates in equal parts from a hydrazine hydrate solution at the temperature of 350 K. The results of X-ray phase analysis indicate the chemical purity of the obtained samples. The values of ε′, ε″ at a frequency of 9 GHz for the NiCo/BaTiO3 system are twice as high compared to NiCo/TiO2 for the corresponding values of the NiCo content, which is due to the higher values of ε′, ε″ of the initial barium titanate. Electrical conductivity of NiCo/BaTiO3 system changes by six orders of magnitude, which indicates the formation of a continuous percolation cluster of metal particles on the surface of dielectric BaTiO3 particles. The composites are heat-resistant up to 630K, as shown by the method of thermogravimetry and pronounced magnetic properties. The program for calculating frequency dependences of reflection and absorption coefficients in a complex form has been developed. EMF absorption for composites from the radiation frequency and the position of the minima of these characteristics, which agree satisfactorily with the experiment. The obtained composites can be promising components for obtaining composite systems and paints for protection against electromagnetic radiation. [ABSTRACT FROM AUTHOR]