Andrei Choukourov

Andrei Choukourov
Charles University in Prague | CUNI · of Macromolecular Physics

Prof., Ing., PhD

About

148
Publications
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Publications

Publications (148)
Article
Full-text available
The design of advanced materials with superb anti-bacterial efficiency by engineering appropriate surface properties has now become a consolidated strategy to improve the functional properties of polymers, metals, and a variety of biomedical materials. Antimicrobial coatings can create a healthier living and working environment and offer holistic s...
Article
Highly porous structures consisting of niobium nanoparticles (Nb NPs) are prepared using magnetron sputtering and inert gas aggregation method. Alongside the thermally-driven evolution of nanoparticle morphology, the microstructural genesis is probed in-situ by x-ray diffraction for the temperature range up to 800 °C. The as-deposited Nb NPs are fo...
Article
In this communication, a new gas aggregation cluster source is introduced equipped with post cylindrical magnetron. The rotation of magnetic circuit improves the usage of cylindrical copper target in terms of its homogenous consumption. Copper nanoparticles were successfully synthesized. Their deposition rate fluctuates at slow rotations of magneti...
Article
Drug-loaded polymers are desirable for the controlled administration of bioactive molecules to biological media because polymer viscoelasticity can be translated into benefits of tissue-contacting materials. Here, we report on plasma-assisted deposition of polyester thin films performed via thermal evaporation of polylactic acid (PLA). The films ca...
Article
Polystyrene/montmorillonite (PS/MMT) composite films with high adsorption activity were prepared via solution intercalation technique followed by treatment of composite films in low-pressure air plasma. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were used to investigate the impact of p...
Article
Among strategies of fuel production, photoelectrochemical water splitting for hydrogen generation is garnering significant attention. The challenge for solar energy harvesting is material development with intense photocatalytic activity, efficient free-charge generation, separation, and transport. Tantalum nitride (Ta3N5) and oxynitrides (Ta3NyOx)...
Article
Colloidal solutions of metal nanoparticles (NPs) are typically produced by multi-step methods using a variety of chemicals. Resultant nanofluids require extra purification steps to remove the reactions by-products and modification steps to introduce anticoagulants for the solution stabilization. Here, we suggest a single-step method to produce nano...
Article
Full-text available
The development of novel biocompatible and biodegradable materials for medical applications has been drawing significant interest in the scientific community for years. Particularly, chitosan loaded with silver nanoparticles (Ag NPs) has a strong antimicrobial potential and could be applied, for example, as wound dressing material. In this work, ch...
Article
In this study, iron carbide nanoparticles (NPs) were prepared by the plasma‐based method using a gas aggregation source of NPs. In‐flight plasma treatment of the NPs was performed to improve their temporal stability. The auxiliary radiofrequency plasma used for the in‐flight treatment resulted in trapping of the NPs in the plasma for several 10s of...
Article
Metal‐polymer nanocomposites have gained increasing attention due to the wide potential applications field. Synthesis of nanoparticles from the gas phase is an intensively studied alternative to the chemical preparation methods. We present a one‐step procedure that combines magnetron‐based gas aggregation cluster source of silver nanoparticles and...
Article
In certain medical interventions, temporally introduced bone implants are required to exhibit high biocompatibility, yet combined with low osseointegration, to allow for their easy removal afterwards. In this work, Ta2O5 surfaces are developed with good biocompatibility and with the osteoblast adhesion regulated by the nano-topography. The surfaces...
Article
The self-organization of macromolecules on solid surfaces represents a topic of great current interest. Here, solvent-free interactions between polyolefins and silicon substrates are investigated upon their physical vapor deposition under vacuum. Molecular dynamics simulations show that polyolefins unfold upon adsorption and that two macromolecules...
Article
Polymer nanoparticles (NPs) can be highly attractive in numerous applications, including biomedicine, where the use of inorganic matter may be detrimental for living tissues. In conventional wet chemistry, the polymerization and functionalization of NPs with specific chemical groups involves complex and often numerous reactions. Here, we report on...
Article
Full-text available
The combination of an atmospheric pressure plasma afterglow operated in air with wet grafting was utilized for the immobilization of chitosan on the surface of polypropylene foil. The plasma treatment results in a local modification of polymer surface along the sample axis with a modified zone of width 2 cm. Moreover, plasma treatment initiates etc...
Article
Carboxyl‐enriched nanoparticles are produced by the plasma polymerization of acrylic acid (ppAA NPs), whereas plasma‐assisted vapor‐phase deposition is used to prepare thin films of poly(ethylene oxide) (ppPEO). Sequential depositions generate phase‐separated coatings. The ppAA NPs are found to be in a glassy state, whereas thin films of ppPEO are...
Article
Kinetic aspects of the synthesis of Ag nanoparticles (NPs) by magnetron sputtering are studied by in situ and time‐resolved small angle X‐ray scattering (SAXS). Part of the NPs are found to become confined within a capture zone at 1–10 mm from the surface of the target and circumscribed by the plasma ring. Three regimes of the NP growth are identif...
Article
Reliable production of nanoparticles (NPs) by magnetron sputtering in a gas aggregation source (GAS) is of great interest because of many potential applications. The size, shape, or structure of NPs can be tuned by the operational parameters of the GAS. In this study, fabrication of copper (Cu) NPs is investigated dependent on the magnetron magneti...
Article
Full-text available
Magnetron sputtering is a well-known technique that is commonly used for the deposition of thin compact films. However, as was shown in the 1990s, when sputtering is performed at pressures high enough to trigger volume nucleation/condensation of the supersaturated vapor generated by the magnetron, various kinds of nanoparticles may also be produced...
Article
Full-text available
Low-temperature plasma treatment of wheat seeds was performed by a plasma jet and dielectric barrier discharge, both at atmospheric pressure. The influence of the plasma treatment on the growth parameters such as root and shoot dry weight and length as well as on the mean germination time was investigated. Stimulation of germination and an increase...
Article
In‐situ UV–Vis spectroscopy was used for investigating the evolution of silver nanoparticles (NPs) inside the gas aggregation cluster source (GAS). The light beam probed the interior of the GAS at different distances from the magnetron. Plasmon resonance was detected at 365 nm, with the highest intensity found close to the magnetron due to the NP t...
Article
The study focuses on the synthesis of two-component heterogeneous nanoparticles with plasma polymer core decorated with silver. It is shown that such strawberry-like particles may be easily produced by the strategy that involves the in-flight deposition of silver onto plasma polymer particles produced by gas aggregation source.
Article
Plasma-assisted vapor-phase deposition of (–CH2–)100 macromolecules is performed onto the surface of pre-deposited polyethylene oxide (PEO). It leads to the formation of two-dimensional 7 nm thick polyethylene (PE) islands of the ramified fractal or ordered dendrite shape. AFM-infrared nanospectroscopy confirms the phase separation whereas compleme...
Article
Copper has strong bactericidal effect against multi-drug resistant pathogens and polyethers are known for their resistance to biofilm formation. Herein, we combined Cu nanoparticles (NPs) and a polyether plasma polymer in the form of nanocomposite thin films and studied whether both effects can be coupled. Cu NPs were produced by magnetron sputteri...
Article
A gas‐phase deposition process based on the combination of nanoparticles (NPs) and thin films is developed to obtain either superhydrophobic or superamphiphilic nanocomposite coatings on filtration membranes. Superhydrophobic membranes are produced on nonwoven viscose fabric and they demonstrate selective absorption of nonpolar organic solvents fro...
Article
A novel technique that enables the production of a-C:H coatings decorated either by sub-micron concave or convex structures is presented. The technique is based on several steps that involve i) pre-seeding of substrates with C:H sub-micron particles produced by a gas aggregation cluster source, ii) overcoating of the C:H particles by thin a-C:H coa...
Article
A tubular magnetron (TMG) was used for in-flight deposition of Cu over Ni nanoparticles (NPs) pre-synthesized in a planar magnetron-based gas aggregation cluster source. The amount of deposited copper was driven by the magnetron current and magnetic field of the TMG. The structure of the resultant NPs was investigated by transmission electron micro...
Article
Magnetron discharge in a cold buffer gas represents a liquid-free approach to the synthesis of metal nanoparticles (NPs) with tailored structure, chemical composition and size. Despite a large number of metal NPs that were successfully produced by this method, the knowledge of the mechanisms of their nucleation and growth in the discharge is still...
Article
Full-text available
In this work, we have applied, for the first time, solution plasma processing of cellulose-containing material to produce cellulose nanocrystals (CNC). The CNC samples produced in three different modes of solution plasma treatment were characterized using methods of dynamic light scattering, infrared spectroscopy, transmission electron microscopy,...
Article
Full-text available
A gas aggregation source based on DC magnetron sputtering was investigated using a passive thermal probe and supplementary diagnostics (Langmuir probe and quartz crystal microbalance). Parameter variations of pressure, axial distance, and magnetron current have been performed for three different targets (pure Cu, pure W, composite Cu/W) in argon di...
Article
Sub-micron polymer particles are highly important in various fields including astrophysics, thermonuclear fusion and nanomedicine. Plasma polymerization offers the possibility to produce particles with tailor-made size, crosslink density and chemical composition to meet the requirements of a particular application. However, the mechanism of nucleat...
Article
Carboxyl-enriched and size-selected polymer nanoparticles (NPs) may prove to be very useful in biomedical applications for linker-free binding of biomolecules and their transport to cells. In this study, we report about the synthesis of such NPs by low-pressure low-temperature pulsed plasma polymerization of acrylic acid. Gas aggregation cluster so...
Chapter
In this chapter, we present results of study an interaction of nanosecond EUV laser pulses at a wavelength of 46.9 nm with lithium fluoride (LiF), caesium iodide (CsI) and golden (Au) samples. The laser beam is focused with a spherical Si/Sc multilayer-coated mirror on samples. Samples were irradiated with 1, 2, 5, 10 and 20 laser shots with variou...
Article
A platinum catalyst undergoes complex deterioration process during its operation as a cathode in a proton exchange membrane fuel cell. By using in situ electrochemical atomic force microscopy (EC-AFM) with super-sharp probes, we quantitatively describe the roughening of platinum thin films during electrochemical cycling to different upper potential...
Article
Full-text available
Nanoparticles composed of multiple silver cores and a plasma polymer shell ([email protected]) were prepared in a single step with a gas aggregation cluster source operating with Ar/hexamethyldisiloxane mixtures and optionally oxygen. The size distribution of the metal inclusions as well as the chemical composition and the thickness of the shells w...
Article
[email protected] core-shell nanoparticles were prepared by a vacuum based method using the gas aggregation source (GAS) of nanoparticles. Ni nanoparticles fabricated in the GAS were afterwards coated by a Ti shell. The Ti shell was deposited by means of magnetron sputtering. The Ni nanoparticles were decelerated in the vicinity of the magnetron to...
Article
Full-text available
This contribution reviews plasma polymer nanoparticles produced by gas aggregation cluster sources either via plasma polymerization of volatile monomers or via radio frequency (RF) magnetron sputtering of conventional polymers. The formation of hydrocarbon, fluorocarbon, silicon- and nitrogen-containing plasma polymer nanoparticles as well as [emai...
Article
Gas aggregation sources are nowadays rather widely used in the research community for producing nanoparticles. However, the direct diagnostics of conditions inside the source are relatively scarce. In this work, we focused on monitoring the plasma parameters and the composition of the gas during the production of the TiOx nanoparticles. We studied...
Article
Core at shell Cu/hydrocarbon plasma polymer nanoparticles (NPs) have been prepared using a gas aggregation cluster source followed by in-flight plasma polymer coating of produced Cu NPs. Conventional plasma polymerization of vapors of n-Hexane or acetone has been applied. It is shown that this strategy for core at shell NPs production enables to ac...
Article
The nanocomposite films Ag/a-C:H were prepared by vacuum-based method which combines deposition of Ag nanoparticles by means of gas aggregation source (GAS) and PECVD deposition of a-C:H matrix. The matrix was deposited in a mixture of Ar and n-hexane on the substrates placed on the powered RF electrode facing the beam of Ag NPs from the GAS. Aniso...
Article
A layer of 14 nm-sized Ag nanoparticles undergoes complex transformation when overcoated by thin films of a fluorocarbon plasma polymer. Two regimes of surface evolution are identified, both with invariable RMS roughness. In the early regime, the plasma polymer penetrates between and beneath the nanoparticles, raising them above the substrate and m...
Article
Full-text available
A number of laser facilities coming online all over the world promise the capability of high-power laser experiments with shot repetition rates between 1 and 10 Hz. Target availability and technical issues related to the interaction environment could become a bottleneck for the exploitation of such facilities. In this paper, we report on target nee...
Article
Plasma polymerized poly(ethylene oxide) (pPEO) thin films were deposited by plasma assisted physical vapor deposition (PAPVD) with a constant thickness of 500 nm. The crosslinking density of pPEO films was controlled through the discharge power. Differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS) were applied to anal...
Article
Full-text available
The process of reduction of Cr6+ ions (solution of potassium dichromate, K2Cr2O7) in a water cathode was studied during a DC discharge in air. The concentration range of Cr6+ was (5.7–19) ×10−5 mol/l and discharge current range was 20–80 mA. Cr6+ ions were shown to be reversibly reduced under a discharge action. The equilibrium degree of reduction...
Article
Plasma polymers are employed in impressive range of applications due to their unique properties. Although films of plasma polymers are traditionally described as smooth and pinhole free, the possibility to produce nanorough and nanostructured plasma polymerized coatings receives increasing attention. In this study, we tested a fully vacuum-based st...
Article
Biomimetic nano-structured films are valuable materials in various applications. In this study we introduce a fully vacuum-based approach for fabrication of such films. The method combines deposition of nanoparticles (NPs) by gas aggregation source and deposition of overcoat thin film that fixes the nanoparticles on a surface. This leads to the for...
Article
Surfaces whose properties change gradually along the sample length, so-called gradient surfaces, are highly interesting for fundamental studies focused on the interaction between biomolecules or cells and surfaces. In this study, we investigate simple, vacuum-based strategy for fabrication of surfaces with gradient nanoroughness and wettability. Th...
Article
In the recent years, highly crosslinked plasma polymers have started to unveil their potential in numerous biomedical application in thin-films form. However, conventional diagnostic methods often fail due to their diverse molecular dynamics conformations. Here, glassy dynamics and the melting transition of thin PEO-like plasma assisted deposited (...
Article
Silver nanoparticle-based antibacterial nanocomposite coatings were fabricated by means of gas aggregation source of Ag nanoparticles and plasma-enhanced chemical vapour deposition of matrix material. Combination of these techniques makes it possible to independently control the amount of Ag nanoparticles in the nanocomposites, as well as propertie...
Article
Immiscible polymer blends tend to undergo phase separation with the formation of nanoscale architecture which can be used in a variety of applications. Different wet-chemistry techniques already exist to fix the resultant polymeric structure in a predictable manner. In this work, an all-dry and plasma-based strategy is proposed to fabricate thin fi...
Article
Full-text available
The jet of reactive effluents produced by surface dielectric barrier discharge was used to deposit PEO-like plasma polymers from di(ethylene) glycol vinyl ether. The jet was confined within the hollow space of either circular cross-section with substrate placed perpendicular to the jet, or rectangular cross-section with the walls used as substrates...
Article
In the present study is shown a novel vacuum-based technique that enables production of hard polymeric nanocomposite coatings with metal (Cu) nanoparticles. This method is based on the use of gas aggregation source (GAS) of Cu nanoparticles and plasma-enhanced chemical vapour deposition of a-C:H matrix that was deposited in a mixture of Ar and n-he...
Article
Plasma treatment of porous materials has huge potential in many applications where chemical modification of interior structure or its loading with polymeric matrices is required. Plasma polymers are often assumed to grow conformally on solid supports; however, their innate roughness may interfere with the surface topography at mesoscale. Here, mode...
Article
Al/AlxOy and Ti/TiOx nanoparticles have been fabricated using gas aggregation cluster source (GAS) equipped with 3-inch planar magnetrons. The main attention has been devoted to the evaluation of the role of oxygen admixture on the deposition rate and properties of formed nanoparticles. It has been found that oxidized nanoparticles are deposited wh...
Conference Paper
This paper reports on the experimental results of interaction of focused XUV laser beam (wavelength 46.9 nm) with Polymethylmethacrylate (PMMA) sample. Laser-beam footprints in the region near the tangential focus of spherical mirror with/without multi-layer reflecting coating are presented and discussed. Reflection coefficients of these two spheri...
Conference Paper
Fluorocarbon plasma polymer nanoparticles have been fabricated using gas aggregation cluster source (GAS) equipped with a planar magnetron with PTFE target. A beam of nanoparticles 20 – 200 nm in diameter was generated. Fluorocarbon nanoparticle films have shown very good water repellent properties. Films immersed in ethanol for two hours exhibited...
Article
In this contribution an effect of dielectric barrier discharge (DBD) sustained in air at atmospheric pressure on surface properties of poly(ethylene terephthalate) (PET) foils is studied. It is found that exposure of PET to DBD plasma leads to rapid changes of surface chemical composition, wettability, surface morphology as well as mechanical prope...
Article
Full-text available
A high-energy, high-yield proton beam with a good homogeneous profile has been generated from a nanosphere target irradiated by a short (30-fs), intense (7×1020W/cm2) laser pulse. A maximum proton energy of 30 MeV has been observed with a high proton number of 7×1010 in the energy range 5-30 MeV. A homogeneous spatial profile with a uniformity (sta...
Article
Back Cover: The growth of columnar silver films was enhanced by deposition over C:H plasma polymer nanoparticles. This enables to prepare columnar structures growing from the particle seeds. The silver was sputtered over the nanoparticles in perpendicular direction and at different angles ranging from 40 to 80°. As an example silver GLAD deposited...
Article
Glancing angle deposition (GLAD) on a smooth substrate has certain limitations, which may be overcome if nanoparticles are deposited first. This study compares the growth of silver columns on a smooth substrate and over pre-deposited small copper (Ø16 nm) and big C:H plasma polymer nanoparticles (Ø110 nm). Cu nanoparticles help to the growth of the...
Article
A new type of a gas aggregation particle source based on a semi-hollow magnetron was developed for production of plasma polymer particles from sputtered nylon. The particles were prepared in a wide range of sizes (from 40 to 270 nm) and at very high deposition rates (up to 1 μm/s) in pure argon working gas. The most important parameter controlling...
Article
Nylon 6,6 foils have been treated by an atmospheric pressure air dielectric barrier discharge. The action of plasma on nylon foils was determined by means of a wide range of techniques that enabled us to study changes in their surface as well as bulk properties. The plasma treatment was found to cause significant changes in morphology, surface chem...
Article
Nanocrystalline diamond (NCD) films may be used in biosensing after modification of their surfaces with active functional groups. Here, surface functionalization of O- and H-NCD films with amine groups was made by 2 plasma-based processes: a) RF plasma treatment in ammonia, b) the deposition of thin amine-containing plasma polymer via RF magnetron...
Article
R. f. magnetron sputtering of poly(tetrafluoroethylene) in configuration of a gas aggregation source is shown to produce super-hydrophobic nano-structured coatings in which cross-linked nano-particles of fluorocarbon plasma polymer are embedded in an uncross-linked continuous (-CF2-)(x), matrix. The 20-30 nm nano-particles appear in proximity of th...
Article
TiO2 nanoparticles and nitrogen-doped TiO2−xNx nanoparticles dispersed in plasma polymer phase are produced by atmospheric pressure DBD in titanium tetraisopropoxide with dry air, mixture of N2 and O2, and 100% N2 used as carrier gases. Energy supply per monomer molecule (the Yasuda parameter) is found to be an important parameter describing the de...