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Modeling of nanofibers interaction with the environment
Klicmanová, I.; Sveshnikov, Alexey
2015 - anglický
Nanomaterials change our life. Every day they find applications in new branches of technology. At the same time, some branches of technology, like civil engineering, are rather conservative and do not accept new approaches lightly. Nanotextiles exhibit a number of qualities that make them a promising material for civil engineering applications. They can potentially play a role of filters, protective layers, armature and others. Properties of the nanotextiles can be significantly influenced by parameters of technological process. Pure experimental search of the optimal technological parameters to achieve the desired properties of the final material can be very tedious. Thus, a theoretical dependence of the properties of the nanotextile on parameters of the technological process must be established. Two independent tasks must be solved for this: the dependence of nanotextile structure on technological parameters, and determination of physical, chemical or biological properties of a nanotextile of a given structure. In this paper we discuss steps necessary for the solution of the second task.
Klíčová slova:
Van der Waals; DLVO potential; Monte Carlo simulations
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Modeling of nanofibers interaction with the environment
Nanomaterials change our life. Every day they find applications in new branches of technology. At the same time, some branches of technology, like civil engineering, are rather conservative and do not ...
Study of photocatalytic activity of Zn.sub.x./sub.Cd.sub.1-x./sub.S quantum dots in dependence on their composition using methylene blue
Praus, P.; Svoboda, L.; Hospodková, Alice; Mamulová Kutláková, K.
2015 - anglický
ZnCdS quantum dots (QDs) with the different composition were prepared by precipitation of zinc and cadmium acetates with sodium sulphide in the presence of cetyltrimethylammonium bromide (CTAB) used for stabilization of their aqueous colloid dispersions. Transition energies of these quantum dots were determined from the UV-VIS spectra of QDs colloid dispersions and consequently used for calculation of the QDs sizes according to the Schrodinger equation. The ZnCdS QDs size was found to be significantly influenced by their composition: the QDs size decreased with the increasing Zn content. The photocatalytic activity of the ZnCdS QDs was studied using the methylene blue decomposition under UV irradiation. Different photocatalytic activity depending on the composition x was observed and explained. The maximal photocatalytic activity was achieved for x = 0.6 when the energy of the irradiation photons was still sufficient to generate electron-hole pairs in majority of the QDs and at the same time the photocatalytic surface area was maximal.\n
Klíčová slova:
quantum dots; ZnCdS; photocatalysis; UV-VIS absorption; x-ray diffraction
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Study of photocatalytic activity of Zn.sub.x./sub.Cd.sub.1-x./sub.S quantum dots in dependence on their composition using methylene blue
ZnCdS quantum dots (QDs) with the different composition were prepared by precipitation of zinc and cadmium acetates with sodium sulphide in the presence of cetyltrimethylammonium bromide (CTAB) used ...
In situ XPS characterization of diamond films after AR.sup.+./sup. cluster ion beam sputtering
Artemenko, Anna; Babchenko, Oleg; Kozak, Halyna; Ukraintsev, Egor; Ižák, Tibor; Romanyuk, Olexandr; Potocký, Štěpán; Kromka, Alexander
2015 - anglický
In this work, in situ XPS analysis of chemical composition of H- and O-terminated nano- and microcrystalline diamond (NCD and MCD) films before and after their sputtering by the Ar+ cluster ion beam was investigated. Scanning electron microscopy confirmed sputtering of all diamond surfaces with a rate about 0.5 nm/min. Raman spectroscopy and XPS revealed surface graphitization of diamond surface induced by sputtering. Moreover, XPS data showed the presence of about 0.7 % of Ar atoms on the investigated diamond surface after 66 min of sputtering. Also, oxygen residuals were still presented on the H-NCD surface after 66 min of sputtering. In contrast, no oxygen was found on the H-MCD surface just after 2 min of sputtering. Surface composition is discussed in respect to the diamond films growth parameters and surface structure.
Klíčová slova:
diamond; depth profiling; XPS; sputtering; Raman
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
In situ XPS characterization of diamond films after AR.sup.+./sup. cluster ion beam sputtering
In this work, in situ XPS analysis of chemical composition of H- and O-terminated nano- and microcrystalline diamond (NCD and MCD) films before and after their sputtering by the Ar+ cluster ion beam ...
Wettability enhancement of polymeric and glass micro fiber reinforcement by plasma treatment
Trejbal, J.; Šmilauer, V.; Kromka, Alexander; Potocký, Štěpán; Kopecký, L.
2015 - anglický
Plasma treatments were used to modify surface properties of polyethylene terephthalate (PET) and glass micro fibers, to improve their wettability. PET fibers, having diameter of 400 μm, and glass fibers (14 μm) were exposed to low pressure oxygen plasma. A direct horizontal optical method was used for contact angle measurements on fiber surfaces submerged into distilled water. Surface morphology changes before and after treatment were characterized by scanning electron microscopy. Finally, cement paste specimens reinforced with PET and lime-based mortars reinforced with glass fibers were made and after 28 days of mixture curing tested by four-point bending tests. After oxygen plasma treatment contact angles decreased by 60 % on PET fibers and by 25 % on glass fibers in comparison with untreated fibers. Next, SEM images revealed the significant surface damages of PET fibers and minor damages of glass fibers. Both four-point tested samples reinforced with treated fibers exhibited the maximum bending strength loss about to 10 to 20 percent compared to samples with untreated reinforcement.
Klíčová slova:
plasma treatments; cool oxygen plasma; wettability; contact angle; micro fibers
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Wettability enhancement of polymeric and glass micro fiber reinforcement by plasma treatment
Plasma treatments were used to modify surface properties of polyethylene terephthalate (PET) and glass micro fibers, to improve their wettability. PET fibers, having diameter of 400 μm, and glass ...
Fabrication methods of diamond coated Love wave SAW biosensors for bacterial detection applications
Drbohlavová, L.; Bulíř, J.; Valeš, Václav; Jákl Křečmarová, M.; Taylor, Andrew; Talbi, A.; Soltani, A.; Mortet, Vincent
2015 - anglický
Pathogen detection has a huge importance in the food industry and it can play significant role in the medical practice. This paper focus on the fabrication methods of diamond coated Love wave surface acoustic wave (LW-SAW) biosensors for bacteria detection. LW-SAW sensors have been fabricated on AT-quartz crystals. Interdigitated transducers have been patterned by RF sputtering and photolithography techniques. Amorphous silicon oxide (SiO2) guiding layer and nano-crystalline diamond layer were both deposited by plasma enhanced chemical vapor deposition at low temperature. Preliminary experimental study of diamond surface termination for sensors bio-functionalization is also reported.
Klíčová slova:
biosensors; LW-SAW
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Fabrication methods of diamond coated Love wave SAW biosensors for bacterial detection applications
Pathogen detection has a huge importance in the food industry and it can play significant role in the medical practice. This paper focus on the fabrication methods of diamond coated Love wave surface ...
Influence of incorporated nanodiamond particles on mechanical properties of composite material based on multi-layer PVA nanofiber textiles
Prošek, Zdeněk; Indrová, K.; Rácová, Z.; Ryparová, Pavla; Nežerka, V.; Topič, J.; Tesárek, Pavel; Kromka, Alexander
2015 - anglický
The present study investigates the influence of NDP on mechanical properties of multi-layer PVA nanofiber textiles. The particles of a diameter equal to 5 nm were incorporated into double- and triple-layer textiles, while the single-layer samples were prepared as the reference. The diameter of PVA nanofibers varied from 100 to 300 nm. We characterized the tensile strength, stiffness and ductility of fabricated nanofibers by using a conventional method – a tensile test. We found that the NDP-enriched nanofibers reveal antibacterial character. However, none or negligible influence of NDP additions on the tested mechanical properties was observed.
Klíčová slova:
nanofibers; PVA; nanodiamonds; electrospinning; mechanical properties; SEM
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Influence of incorporated nanodiamond particles on mechanical properties of composite material based on multi-layer PVA nanofiber textiles
The present study investigates the influence of NDP on mechanical properties of multi-layer PVA nanofiber textiles. The particles of a diameter equal to 5 nm were incorporated into double- and ...
Fabrication of 3D diamond membranes for microfluidic systems
Varga, Marián; Babchenko, Oleg; Bauerová, Pavla; Hruška, Karel; Jurka, Vlastimil; Kromka, Alexander; Rezek, Bohuslav
2015 - anglický
Perfusion of cell medium, especially in microfluidic devices, can provide in-vivo-like conditions for cell cultures. The most recent demand on such systems is to include electronically active artificial cell support for in-situ monitoring. Diamond thin films exhibit advantageous combination of physical, mechanical, chemical, biocompatible and electronic properties for this purpose. In this work we explore two strategies for fabrication of self-standing three-dimensional nanocrystalline diamond membrane for implementation in microfluidic invivo like experiments: i) nucleation and chemical vapour deposition (CVD) growth of diamond on porous 3D carbon foam (with 80 pores per inch) and ii) selective diamond growth predefined by photolithographic processing using copper grid mask. The morphology and material quality of the fabricated membranes are characterized by scanning electron microscopy and Raman spectroscopy.
Klíčová slova:
nanocrystalline diamond; membranes; microwave plasma; microfluidics; carbon foam
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Fabrication of 3D diamond membranes for microfluidic systems
Perfusion of cell medium, especially in microfluidic devices, can provide in-vivo-like conditions for cell cultures. The most recent demand on such systems is to include electronically active ...
(100) substrate processing optimization for fabrication of smooth boron doped epitaxial diamond layer by PE CVD
Mortet, Vincent; Fekete, Ladislav; Ashcheulov, Petr; Taylor, Andrew; Hubík, Pavel; Trémouilles, D.; Bedel-Pereira, E.
2015 - anglický
Boron doped diamond layers were grown in an SEKI AX5010 microwave plasma enhanced chemical vapour deposition system. Effect of surface preparation, i.e. polishing and O2/H2 plasma etching on epitaxial growth on type Ib (100) HPHT synthetic diamonds were investigated. Using optimized substrate preparation, smooth (RRMS ~ 1 nm) boron doped diamond layers with metallic conduction and free of un-epitaxial crystallites were grown with a relatively high growth rate of 3.7 μm/h. Diamond were characterized by optical microscopy, optical profilometry, atomic force microscopy and Hall effect.
Klíčová slova:
doping; PE CVD; diamond; surface treatment; thin film
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
(100) substrate processing optimization for fabrication of smooth boron doped epitaxial diamond layer by PE CVD
Boron doped diamond layers were grown in an SEKI AX5010 microwave plasma enhanced chemical vapour deposition system. Effect of surface preparation, i.e. polishing and O2/H2 plasma etching on epitaxial ...
Doped DLC coatings for biomedical applications
Písařík, Petr
2015 - anglický
Nowadays there are materials having excellent properties for use in medicine (Diamond-like carbon, Hydroxyapatite, …). Diamond-like carbon (DLC) is a metastable form of amorphous carbon containing bonded carbon atoms of sp2 and sp3 hybridized orbital. DLC layers are semiconductors with high mechanical hardness, chemical inertness, low coefficient of friction, high thermal conductivity, good electrical and optical properties, biocompatibility and no cytotoxicity. All properties of the films are not always ideal, so it is necessary to modify the layer. One example of how to modify the properties of thin layers are dopations. The incorporation of dopants in films may lead to greater multifunctionality and much improved properties. Most modifications were made to modify contact angle and surface energy, to reduce internal stresses, to decrease surface roughness, coefficient of friction or wear....
Klíčová slova:
silver doped; diamond like carbon; thin layers; mechanical properties
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Doped DLC coatings for biomedical applications
Nowadays there are materials having excellent properties for use in medicine (Diamond-like carbon, Hydroxyapatite, …). Diamond-like carbon (DLC) is a metastable form of amorphous carbon containing ...
Initial study of structure of nanofiber textiles and the creation of its model
Havrlík, M.; Sveshnikov, Alexey
2015 - anglický
In this research, the structure of the fabrics was analyzed using an electron scanning microscope Tescan Maia 3. Two sets of the experiments have been carried out. In the first experiment the surface structure of the samples was studied. Photos created by SEM were analyzed using program Atlas and image editor GIMP. In this set of the experiments the initial parameters for the creation of a digital 2D model of a single layer have been determined (fiber size distribution, pore size and curvature of the fibers). In the second set of the experiments cross sections of nanofiber textiles were made in order to study the inner structure of the fabric. This information allows evaluation of the total number of 2D layers in the model and, thus, is very important for future creation of a 3D model of the fabric.
Klíčová slova:
polymer; SEM photography
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Initial study of structure of nanofiber textiles and the creation of its model
In this research, the structure of the fabrics was analyzed using an electron scanning microscope Tescan Maia 3. Two sets of the experiments have been carried out. In the first experiment the surface ...
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