National Repository of Grey Literature 18 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Low temperature plasma and nanoparticles: effects of gas flow and surfaces
Ali-Ogly, Suren ; Kousal, Jaroslav (advisor) ; Blažek, Josef (referee) ; Kudrna, Pavel (referee)
Title: Low temperature plasma and nanoparticles: effects of gas flow and surfaces Author: Ing. Suren A. Ali-Ogly, B.Eng Department / Institute: Department of Macromolecular Physics / Charles University Supervisor of the doctoral thesis: Mgr. Jaroslav Kousal, PhD, Department of Macromolecular Physics / Charles University Abstract: This PhD thesis investigates the role of carrier gas flow in the magnetron-based gas aggregation cluster source and its impact on nanoparticle transportation. The research encompasses both theoretical and experimental aspects of low-temperature plasma interaction with surfaces and material engineering applications. Numerical models and computational fluid dynamics simulations are employed to understand the underlying physics of nanoparticles motion in gas aggregation cluster sources. The study demonstrates that carrier gas flow, particularly its velocity and inlet configuration, significantly influences the nanoparticles trap region and their residence time in the plasma. Brownian diffusion is identified as a critical factor affecting the spatial behaviour of NPs, contributing to both their escape and loss in gas aggregation cluster sources. The deposition of thin films using magnetron sputtering of PLA, a promising polymer material, is shown to facilitate nanoparticle adhesion....
Diagnostics of plazma in the deposition sources using the Langmuir probes
Šedivý, Petr ; Kousal, Jaroslav (advisor) ; Kylián, Ondřej (referee)
This experimental work is concerned with measurement of elementary characteristics of plasma - potential of plasma, electron temperature and density of particles. As research methods were selected the Langmuir probes - especially the single probe. At the beginning of the thesis there are explained shortly the elementary characteristics of plasma and the procedure of determination particular parameters of the plasma from the volt-ampere characteristics of the probe. The third chapter is focused on description of the experiment, the probe, the apparatus and its control. Plasma measured within this work originated from the new hollow magnetron which will serve as future source of nanoparticles. Results of the work are focused on the description of individual parameters of the plasma in dependence on other variables such as the magnetron power, pressure of gas, spatial dependence or presence of additional auxiliary magnetic field.
Heterogeneous metal-plasma polymer nanoparticles prepared by means of gas aggregation sources
Štefaníková, Radka ; Kylián, Ondřej (advisor) ; Kousal, Jaroslav (referee)
The field of nanoparticle preparation is nowadays rapidly evolving. Most of the ap- proaches can be classified as wet chemistry techniques. On the other hand, gas aggrega- tion sources offer an alternative, purely physical approach of how to fabricate nanoparti- cles in a controlled and reproducible manner. Many kinds of nanoparticles were already produced in this way, e.g. metallic, metal oxides or plasma polymer nanoparticles. Moreover, as it was demonstrated in recent studies, even heterogeneous nanoparticles by combining more types of materials may be produced by such sources. Among them, an increasing interest is devoted to the metal/plasma polymer nanoparticles. Concerning the production of metal/plasma polymers nanoparticles, the majority of so far published studies focused on the nanoparticles with metallic cores surrounded by a plasma polymer overcoat. Because of this, we decided to investigate a novel two- step deposition procedure for the production of metal/plasma polymer nanoparticles with inverse structure, i.e. nanoparticles with plasma polymer cores covered by metal. This method is based on the gas aggregation technique for plasma polymer nanoparticle fabrication (C:H:N:O in this study) followed by subsequent in-flight coating by sputtered metal (silver, copper and titanium). The production...
Fabrication of metal nanoclusters and their characterization
Kratochvíl, Jiří ; Kylián, Ondřej (advisor) ; Kousal, Jaroslav (referee)
Copper nanoclusters have potencial for fabrication of nanostructured surfaces, which can be used in electronics, electrotechnics, optics and in biomedical applications. To create such surfaces, it is necessary to create and characterize the nanoclusters deeply first and this is the main topic of this work. First, we found repeatable procedure to create copper nanoclusters by the gas aggregation nanocluster source. We studied homogenity of prepared surfaces by quartz crystal microbalance and optical ellipsometry, we determined conditions for deposition of homogeneous coatings. Next, we studied deposition rate in dependence on the magnetron current, pressure in the aggregation and deposition chambers. Deposition rate linearly increased with current, but in low currents it was nearly zero. Furthermore, we found maximum deposition rate for a given pressure in the aggregation chamber and determined the range of pressure in deposition chamber where it is possible to deposit thin films of copper nanoclusters. This is important for fabrication of nanocomposite surfaces. We studied also the size, shape of nanoclusters and growth of surface by scanning electron microscope. The surfaces were very porous. We measured roughness and optical absorbance where anomalous optical absorption was found. Finally, we found that...
Study of the interaction of nanocomposite films with plasma
Steinhartová, Tereza ; Hanuš, Jan (advisor) ; Kousal, Jaroslav (referee)
The theoretical part deals with basic characteristics of low-temperature, low-pressure plasma. It describes the principles of preparation of nanocomposite films using this type of plasma and also the etching process in chemically active plasma. It further explains the basic principles of methods used to characterize our samples. The experimental part describes the process of optimalization of chemically active plasma ($O_2/Ar$) employed for etching of plasma polymer films. After finding suitable etching parameters several types of films were prepared. First, films of plasma polymer and then nanocomposite films composed of metal and plasma polymer. Afterwards the samples were treated in defined conditions of oxygen plasma. The aim was to study the physico-chemical properties of these films, especially their chemical composition using X-ray photoelectron spectroscopy, and wettability. Attention was given to the change of the water contact angle as a function of etching time and morphology of the pample. In case of oxygen etching ageing of the film was studied. By increasing of roughness superhydrophobic (SHF) film was prepared.
Diagnostics of plasmas for technological applications
Turek, Zdeněk ; Kudrna, Pavel (advisor) ; Kousal, Jaroslav (referee)
The subject of the master thesis is the extension of the measurement of plasma para- meters by the Langmuir probe in a system with a planar magnetron and a hollow cathode operating in pulse mode. The main tasks are to modify the measuring circuit to increase the maximum probe current and to put the USB oscilloscope into operation for data collection with higher resolution and higher sampling rate. Furthermore, the function of the entire device will be verified using test circuits and also by measuring the probe characteristics in discharges in a system with a magnetron and a hollow cathode in both continuous and pulse mode. 1
Diagnostics of plasmas for technological applications
Turek, Zdeněk ; Kudrna, Pavel (advisor) ; Kousal, Jaroslav (referee)
The subject of the master thesis is the extension of the measurement of plasma para- meters by the Langmuir probe in a system with a planar magnetron and a hollow cathode operating in pulse mode. The main tasks are to modify the measuring circuit to increase the maximum probe current and to put the USB oscilloscope into operation for data collection with higher resolution and higher sampling rate. Furthermore, the function of the entire device will be verified using test circuits and also by measuring the probe characteristics in discharges in a system with a magnetron and a hollow cathode in both continuous and pulse mode. 1
Heterogeneous metal-plasma polymer nanoparticles prepared by means of gas aggregation sources
Štefaníková, Radka ; Kylián, Ondřej (advisor) ; Kousal, Jaroslav (referee)
The field of nanoparticle preparation is nowadays rapidly evolving. Most of the ap- proaches can be classified as wet chemistry techniques. On the other hand, gas aggrega- tion sources offer an alternative, purely physical approach of how to fabricate nanoparti- cles in a controlled and reproducible manner. Many kinds of nanoparticles were already produced in this way, e.g. metallic, metal oxides or plasma polymer nanoparticles. Moreover, as it was demonstrated in recent studies, even heterogeneous nanoparticles by combining more types of materials may be produced by such sources. Among them, an increasing interest is devoted to the metal/plasma polymer nanoparticles. Concerning the production of metal/plasma polymers nanoparticles, the majority of so far published studies focused on the nanoparticles with metallic cores surrounded by a plasma polymer overcoat. Because of this, we decided to investigate a novel two- step deposition procedure for the production of metal/plasma polymer nanoparticles with inverse structure, i.e. nanoparticles with plasma polymer cores covered by metal. This method is based on the gas aggregation technique for plasma polymer nanoparticle fabrication (C:H:N:O in this study) followed by subsequent in-flight coating by sputtered metal (silver, copper and titanium). The production...
Tailoring of structure of plasma polymers
Krtouš, Zdeněk ; Kousal, Jaroslav (advisor) ; Matoušek, Jindřich (referee)
The thesis was targeted on the preparation of thin film plasma polymers with Plasma assisted vapour thermal deposition technique. As a characterised precursor was chosen the poly lactic acid because of its interesting biodegradable properties. The set of samples prepared with varying plasma power was obtained. It was found that the PLA structure is still preserved after repolymerisation, moreover, new carbon rich compound was formed. The strong changes of behaviour of samples in water were observed around plasma power of 30 W. The sample prepared in weaker plasma had properties of hydrogel. The samples prepared above 30 W of plasma power were solid and did not dissolve in water.

National Repository of Grey Literature : 18 records found   1 - 10next  jump to record:
See also: similar author names
1 Kousal, Jakub
1 Kousal, Jan
2 Kousal, Jiří
Interested in being notified about new results for this query?
Subscribe to the RSS feed.