Suchergebnisse

Polytetrafluoroethylene (PTFE, teflon) possesses excellent stability and low surface energy, which enables its extensive use in the manufacture of biomimetic superhydrophobic surfaces. We proposed a simple and fast method for producing superhydrophobic surfaces by treating the teflon plate by nanosecond pulse infrared irradiation by means of CO2 laser. The surface relief was visualized by scanning electron microscope. The surface wettability was estimated by measuring the contact angle. The treated teflon superhydrophobic surfaces with static contact angle up to 154°demonstrated self-cleaning properties. The creation of regular two-dimensional structures leading to super-adhesive property of the teflon surface was shown. Thus, it was shown that the surface treating of teflon by nanosecond infrared laser could be used for creation of the super-hydrophobic surfaces for various applications such as self-cleaning, microfluidic devices, and the laboratory-on-chip systems. © Published under licence by IOP Publishing Ltd. ; Government Council on Grants, Russian Federation ; Ministry of Science and Higher Education of the Russian Federation: 3.9534.2017/8.9, 3.7046.2017/7.8 ; The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation (projects 3.9534.2017/8.9 and 3.7046.2017/7.8) and by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" Ural Federal University was used.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Government of the Russian Federation ; Project CICECO-Aveiro Institute of Materials - national funds through the FCT/MEC ; FEDER under the PT2020 Partnership Agreement ; CNPq: 304604/2015-1 ; CNPq: 400677/2014-8 ; Government of the Russian Federation: 16-02-00821-a ; Government of the Russian Federation: 02. A03.21.0006 ; Project CICECO-Aveiro Institute of Materials - national funds through the FCT/MEC: FCT UID/CTM/50011/2013 ; CNPq: 232241/2014-7 ; Thickness dependence of imprint and polarization dynamics of Pb1-xLax(Zr1-yTiy)(1-x/4)O-3 (PLZT) thin films is reported in this work. Asymmetries in the histograms of the local piezoresponse reveal an imprint effect in the studied films whose origin could be associated to Schottky barriers near the film-substrate interface. Time-resolved spectroscopic measurements shows that the local polarization relaxation follows the exponential dependence . A maximum relaxation time approximate to 2.18s was observed for the 350nm thick film. A similar thickness dependence between grain size, correlation length () and relaxation time () suggest an intrinsic relationship between them.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Russian Foundation for Basic Research ; Government of the Russian Federation ; FCT/MEC ; FEDER ; CNPq: 304604/2015-1 ; CNPq: 400677/2014-8 ; CNPq: 232241/2014-7 ; Russian Foundation for Basic Research: 16-02-00821-a ; Government of the Russian Federation: 02.A03.21.0006 ; FCT/MEC: FCT UID/CTM/50011/2013 ; La-modified lead zirconate titanate (PLZT) thin films were prepared to study their physical properties at macro- and nanoscale. Piezoresponse force microscopy (PFM) studies suggest a local imprint behavior at room temperature. Confirmed by P-E hysteresis loops recorded at 180-300K, the imprint effect at room temperature tends to disappear at lower temperatures. In addition, the remanent polarization gradually increases and then decreases after reaching a maximum at around 243K. This behavior suggests the occurrence of a reentrant dipole glass or an activated electric field effect in the studied PLZT films.

We have studied the formation of isolated domains induced by ion beam irradiation in the stoichiometric lithium niobate (SLN) single crystals covered by surface dielectric layer. The unusual domain shape was revealed at the irradiated polar surface at the doses above 20 pC. The nested domain shape with hexagonal outer part and circle inner one has been distinguished. The domains visualization in the bulk showed the hexagonal domain shape in the depth. The obtained effect was attributed to backswitching under the action of electric field produced by space charge dipped to LN plate at the doses above 20 pC due to essential ion beam sputtering effect. ; The equipment of the Ural Center for Shared Use "Modern nanotechnology" UrFU was used. The research was made possible in part by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006) and by President of Russian Federation grant for young scientists (Contract 14.Y30.16.8441-MK).

In this report, we present a detailed study of the formation of alumina nanostructures at the surface of aluminium plate by hot water treatment (HWT) at various temperatures. The nanostructures were studied by scanning electron microscopy. The superhydrophilic property of the treated surface was revealed and its stability was investigated. It was shown that HWT could be used also for synthesis of the aqueous suspensions of alumina nanoparticles. It is proposed that the method can be applied for production of surface nanostructures and nanoparticles of various metal oxides. © Published under licence by IOP Publishing Ltd. ; Government Council on Grants, Russian Federation ; Ministry of Science and Higher Education of the Russian Federation: 3.4993.2017/6.7, 3.9534.2017/8.9 ; Ural Federal University, UrFU: 2.2.2.17.D-18/36 ; E.A.M. acknowledges the support from the Ural Federal University (grant for young scientist No. 2.2.2.17.D-18/36). The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation (projects 3.9534.2017/8.9 and 3.4993.2017/6.7) and by Government of the Russian Federation (act 211, agreement 02.A03.21.0006). The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" Ural Federal University was used.

We demonstrate the application of confocal Raman microscopy (CRM) for nondestructive imaging of ferroelectric domains both at the surface and in the bulk of lead magnesium niobate-lead titanate (PMN-PT) ferroelectric single crystals. The studied model periodical domain structure was created at a [001] cut of tetragonal-phase PMN-PT crystal by the electron beam patterning technique. It was shown that the surface CRM domain image coincides in details with the image obtained by piezoresponse force microscopy. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. ; The research was funded by Russian Foundation for Basic Research (grant 17-52-80116-BRICS_a), National Natural Science Foundation of China (grant 51761145024), Government of the Russian Federation (act 211, agreement 02.180 A03.21.0006), and Ministry of Science and Higher Education of the Russian Federation (state task No. 3.4993.2017/6.7).

We demonstrate the abilities of various SEM techniques for domain imaging in PMN-PT crystals with different compositions. It is shown that the imaging of the chemically etched relief is limited by its destructivity and potential contrast - by low resolution and contrast instability. The optimal parameters of the imaging by backscattered electron channelling allow obtaining the high-resolution domain imaging in PMN-PT crystals. The domain structure change as a result of the phase transition are imaged. The correlation between the images of the surface domain structure obtained by scanning electron microscopy and piezoresponse force microscopy is demonstrated. © 2018 Institute of Physics Publishing. All rights reserved. ; The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" Ural Federal University has been used. The research was made possible by RFBR (grant 17-52-80116-BRICS_a) and state task of Ministry of education and science of the Russian Federation (No. 3.4993.2017/6.7). The work was partially supported by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). ; et al.;NT-MDT Spectrum Instruments;Ostec-ArtTool Ltd.;Promenergolab LLC;Russian Foundation for Basic Research;Taylor and Francis Group

We have studied the influence of initial domain structure on piezoelectric and dielectric properties of Sr 0.61 Ba 0.39 Nb 2 O 6 single crystals slightly doped with Ce and Ni. Initial domain structure was created by zero-field cooling, in-field cooling, and partial switching. The difference in the frequency dependences of macroscopic piezoelectric response and temperature dependences of dielectric permittivity for various initial domain structures was revealed. © 2018 Institute of Physics Publishing. All rights reserved. ; Equipment of the Ural Centre for Shared Use "Modern nanotechnology" Ural Federal University was used. The research was made possible by Russian Foundation of Basic Research (project № 16-02- 00821-а) and state task of Ministry of education and science of the Russian Federation (No. 3.4993.2017/6.7). The work was partially supported by Government of the Russian Federation (act 211, agreement 02.A03.21.0006). Part of this work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID /CTM /50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. ; et al.;NT-MDT Spectrum Instruments;Ostec-ArtTool Ltd.;Promenergolab LLC;Russian Foundation for Basic Research;Taylor and Francis Group

We have studied a dense domain structure (DDS) appearing during polarization reversal in rhombohedral (111)-cut lead magnesium niobate-lead titanate single crystals. The complicated shape of the switching current was explained by means of non-uniform motion of the boundary between the DDS and c-domains using comparative analysis of the optical current and kinetic map. 2D-vector piezoresponse force microscopy revealed that DDS represented needle-like a-domains inside the a-domains with different vertical orientations of spontaneous polarization. © 2020 Author(s). ; The equipment of the Ural Center for Shared Use "Modern Nanotechnology" UrFU was used. This work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation under Project No. 3.9534.2017/8.9, by the Government of the Russian Federation (Act 211, Agreement No. 02.180 A03.21.0006) and by RFBR (Grant No. 17-52-80116-BRICS_a). This work was supported by the NSFC projects (Grant No. 51761145024), Shaan Xi province Project (Nos. 2017 ktpt-21 and 2018TD-024), and the 111 Project under Grant No. B14040.

Production of non-spherical crystalline nanoparticles by laser ablation in liquid has been demonstrated recently. Here we studied the shape variety of PbO nanoparticles prepared by laser ablation in deionized water and IPA. The key role of water in the formation of PbO non-spherical nanostructures was demonstrated. Only spherical nanoparticles have been obtained in isopropyl alcohol (IPA). PbO non-spherical nanostructures have been formed only in presence of water, which supports the growth mechanism by oxidation. Using mixture of IPA and water in various proportions and revealing the time and temperature dependences of non-spherical nanostructure morphology can be used for controlled growth of PbO non-spherical nanostructures. © Published under licence by IOP Publishing Ltd. ; Government Council on Grants, Russian Federation ; Ministry of Science and Higher Education of the Russian Federation: 3.4993.2017/6.7, 3.9534.2017/8.9 ; The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation (projects 3.9534.2017/8.9 and 3.4993.2017/6.7) and by Government of the Russian Federation (act 211, agreement 02.A03.21.0006). The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" Ural Federal University was used.

Ferroelectric materials based on lead zirconate titanate (PZT) are widely used as sensors and actuators because of their strong piezoelectric activity. However, their application is limited because of the high processing temperature, brittleness, lack of conformal deposition, and a limited possibility to be integrated with the microelectromechanical systems (MEMS). Recent studies on the piezoelectricity in the 2-D materials have demonstrated their potential in these applications, essentially due to their flexibility and integrability with the MEMS. In this work, we deposited a few layer graphene (FLG) on the amorphous oxidized Si3N4 membranes and studied their piezoelectric response by sensitive laser interferometry and rigorous finite-element modeling (FEM) analysis. Modal analysis by FEM and comparison with the experimental results show that the driving force for the piezoelectric-like response can be a polar interface layer formed between the residual oxygen in Si3N4 and the FLG. The response was about 14 nm/V at resonance and could be further enhanced by adjusting the geometry of the device. These phenomena are fully consistent with the earlier piezoresponse force microscopy (PFM) observations of the piezoelectricity of the graphene on SiO2 and open up an avenue for using graphene-coated structures in the MEMS. © 1986-2012 IEEE. ; This work was supported in part by the Russian Foundation or Fundamental Research under Grant 16-29-14050, in part by the Ministry of Education and Science of the Russian Federation in the framework of the Increase Competitiveness Program of MISiS under Grant K2-2019-015, in part by the Project CICECO-Aveiro Institute of Materials financed by national funds through the Portuguese Foundation for Science and Technology/MCTES under Grants UIDB/50011/2020 and UIDP/50011/2020, and in part by the Center for Nanophase Materials Sciences, which is a Department of Energy Office of Science User Facility. The work was also supported by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006) and by the Ministry of Science and Higher Education of the Russian Federation (state task FEUZ-2020-0054). The equipment of the Ural Center for Shared Use "Modern nanotechnology" UrFU was used. The work of Yakov Kopelevich was supported in part by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and in part by the Fundação de Amparo à Pesquisa do Estado de S. Paulo (FAPESP) (Brazil).

We studied microstructure, surface morphology, and domain structure of (Ba 0.75 ,Sr 0.25 )TiO 3 based glass-ceramics with different amount of Mn additive (from 0 to 0.5%) prepared from melted and quenched mixed powders using several microscopic methods. The as-quenched sample was annealed and subjected to a controlled crystallization in air for 2h at temperatures 850 and 950?C. It was shown that the addition of the Mn up to 0.5% had no impact on morphology and domain structure. The dendrite structure was revealed in the samples crystallized at 850?C. The geometry of the clusters was analysed in terms of fractal approach. The faceted grains with size about 150 nm were found in ceramics annealed at 950?C. Individual grains demonstrated non-uniform piezoresponse, which could be attributed to existence of domain structure. © 2018 Institute of Physics Publishing. All rights reserved. ; The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" Ural Federal University was used. The research was made possible by Russian Foundation for Basic Research (grant 18-52-53032) and state task of Ministry of education and science of the Russian Federation (No. 3.4993.2017/6.7). The work was supported partially by Government of the Russian Federation (act 211, agreement 02.A03.21.0006). ; et al.;NT-MDT Spectrum Instruments;Ostec-ArtTool Ltd.;Promenergolab LLC;Russian Foundation for Basic Research;Taylor and Francis Group

Samarium substituted bismuth ferrite (BiFeO3) ceramics prepared by sol-gel synthesis method were studied using both local scale and microscopic measurement techniques in order to clarify an evolution of the crystal structure of the compounds across the morphotropic phase boundary region. X-ray diffraction analysis, transmission and scanning electron microscopies, XPS, EDS/EDX experiments and piezoresponse force microscopy were used to study the structural transitions from the polar active rhombohedral phase to the anti-polar orthorhombic phase and then to the non-polar orthorhombic phase, observed in the Bi1−xSmxFeO3 compounds within the concentration range of 0.08 ≤ x ≤ 0.2. The results obtained by microscopic techniques testify that the compounds in the range of 0.12 ≤ x ≤ 0.15 are characterized by two phase structural state formed by a coexistence of the rhombohedral and the anti-polar orthorhombic phases; two phase structural state observed in the compounds with 0.15

Female white rats were exposed during up to 6 months 5 times a week, 4 hr per day in a "nose only" inhalation device to an aerosol containing predominantly submicron (nanoscale included) particles of amorphous silica in the concentration 2.6±0.6 or 10.6±2.1 mg/m3. In an auxiliary experiment with a single-shot intratracheal instillation of these particles, it was shown that they induced a pulmonary cell response comparable with that to highly cytotoxic and fibrogenic standard quartz powder DQ12. However, in the long-term inhalation test, the studied aerosol proved to be of very low systemic toxicity and fibrogenicity. This paradox may be explained by low SiO2 retention in lungs and other organs due to a relatively high in vivo solubility of these nanoparticles. Nevertheless, their genotoxic action and transnasal penetration into the brain should make one give a cautious overall assessment of this aerosol as an occupational or environmental hazard. © Published under licence by IOP Publishing Ltd. ; Government Council on Grants, Russian Federation ; Ministry of Science and Higher Education of the Russian Federation: 3.9534.2017/8.9 ; The research was partially supported by the Ministry of Science and Higher Education of the Russian Federation (project 3.9534.2017/8.9) and by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" UrFU was used.

Nanoparticles (NPs) of Fe3O4 were produced by a chemical technique and NPs of Ag, Au, CuO, NiO, Mn3O4, PbO, ZnO, TiO2, SiO2, and Al2O3 - by laser ablation in water. In some experiments we compared particles of a given chemical composition having different diameters, while in others - equidimensional NPs of different metals or metal oxides (Me-NPs). We used two experimental models: a single intra-tracheal instillation of Me-NPs 24 h before the bronchoalveolar lavage procedure (collecting) and the repeated intra-peritoneal injections during 6-7 weeks in non-lethal doses. Besides, we carried out long-term inhalation experiments with NPs of Fe2O3, SiO2, and NiO. We have demonstrated that NPs are much more noxious than their fine micrometric or even submicron counterparts and are usually the more toxic the smaller their dimensions within the nanoscale range. We have found also that toxicity of Me-NPs strongly depends on their chemical nature, solubility, and specific mechanisms of characteristic action of a given metal in any chemical form. Solubility of Me-NPs in biological milieus plays an important role in their toxicokinetics, which can prevail over that of the physiological mechanisms controlling their distribution, retention, and elimination. On the other hand, thanks to the high activity of these mechanisms, the organism is not defenceless against the impact of Me-NPs. The toxicity and even genotoxicity of Me-NPs can be significantly decreased by adequately composed combinations of some bioactive agents in innocuous doses. © 2018 Institute of Physics Publishing. All rights reserved. ; The experiments were planned and implemented in accordance with the «International guiding principles for biomedical research involving animals» developed by the Council for International Organizations of Medical Sciences (1985) and were approved by the Bio-Ethics Committee of the Yekaterinburg Medical Research Centre for Prophylaxis and Health Protection in Industrial Workers. ; The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" Ural Federal University was used. The work was partially supported by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006) and the state task of Ministry of education and science of the Russian Federation (No. 3.4993.2017/6.7). ; et al.;NT-MDT Spectrum Instruments;Ostec-ArtTool Ltd.;Promenergolab LLC;Russian Foundation for Basic Research;Taylor and Francis Group