The work concerns in modern surface treatment, such as cold plasma. The main aim of this work was to find out the effect of plasma treatment on the surface of wood applied before glue treatment which is influential in final quality of glueing. The work compares the firmness of glued joint of solid wood-fibre slab -- HDF and locust tree on groups of samples of treated and non-treated surface in different plasma discharges. The first part of the work comprises a summary of knowledge in the plasma field and glueing and it attempts to establish a general overview of present development in research in the field of examined issue. The second part of the work deals with method of performed experiment according to the researched norms. Results of the work have proven that plasma preparatory treatment influences the firmness of glueing and at a certain type of use of plasma discharge we can improve the quality of glued joint.

The diploma work deals with the preparation of biocompatible hydrophilic layers from a propane-butane mixture by plasma polymerization. Subsequent characterization of the layers was performed using both biological (antibacterial tests and biocompatibility test) and physico-chemical diagnostics (SEM, OES and surface energy determination). The theoretical part presents the basic principle of dielectric barrier discharge, its use and various types, including surface dielectric barrier discharge (SDBD), which was used during deposition. Next, cell cultures, cell morphology and clarification of the term biocompatibility were described. At the end of the theoretical part, all used during the experimental part of the diagnostics were also described. In the experimental part, the procedure of deposition of hydrophilic layers and the overall apparatus, which was used during deposition, were presented. Prior to the characterization of the samples, the discharge was diagnosed using optical emission spectroscopy. Furthermore, the level of hydrophilicity of the layers and their elemental composition on the surface was determined. Biological tests for biocompatibility and antibacterial properties provided information on the viability of the cells on the layers and their antibacterial effects.

Theoretical part of diploma thesis was focused on the search of the state of knowledge in the area of plasma, plasma polymerization and characterization of thin films. Plasma-enhanced chemical vapor deposition (PECVD) was described in the experimental part together with selected analytical techniques. The technology with high level of reproducibility was reached by precise control of deposition conditions, monitoring of plasma, and analysis of plasma products using mass spectrometry. The obtained results demonstrated that the elemental composition, chemical structure, optical and mechanical properties of films were influenced by effective power used.

The theoretical part deals with basic characteristics of low-temperature, low-pressure plasma. It also describes the principles of preparation of polymer and nanocomposite films using this type of plasma. It further explains the basic principles of methods used to characterize our samples. The experimental section shows a technology to produce hard polymeric coatings with metal (Cu) nanoparticles (NPs) fabricated by gas aggregation source (GAS). This approach has an important advantage that Cu concentration and matrix properties can be controlled independently. Characterization of the films in terms of chemical composition, morphology, optical and mechanical properties is described here alongside with description of Cu NPs production using GAS with variable aggregation length. The a- C:H matrix was deposited in a mixture of Ar and n-hexane on the substrates placed on a RF electrode. The beam of the NPs was normal to the substrate plane. In this arrangement it was possible to control hardness of the films and by operational parameters of the GAS also the amount of the NPs in the film. In the last section fabrication of nanocomposite films of titanium and nylon NPs is shown. Powered by TCPDF (www.tcpdf.org)

The thesis deals with the surface modification of cotton fabric by low-pressure micro-wave plasma discharge. The main materials used for this experiment are cotton fabrics and hexamethyldisiloxane. The experiment itself is focused on the modification of cotton fabric to improve hydrophobic atributes. An argon process gas was used in the surface modification. The individual treated samples were operated with changes in process gas flow and the time during which the above-mentioned modifications was performed. Two methods were used to analyze the results of the experiment. The first one was aimed at determining changes in hydrophobic atributes in the form of wetta-bility in an unmodified sample compared to other modificated samples using the drop-let method. An electron microscope was used for the subsequent study of possible changes in surface topography. From the point of view of the examined results, the difference in hydrophobic properties was observed when using the droplet method to-gether with the change in the topography of the surface obtained on the electron mi-croscope in the cotton samples examined. The actual evaluation of individual methods points to the desirable changes in modified cotton compared to unmodified cotton. Further information regarding the results of the experiment, depending on the changes in individual parameters in the cotton treatment process using low pressure microwave plasma discharge, are presented in thesis.

The doctoral thesis deals with the experimental study of the low-temperature plasma designated for the preparation of thin films using the method of physical sputtering. It describes measurements which were realized on two types of devices - on the low-pressure plasma jet sputtering system and on the planar magnetron. The plasma diagnostics in the discharge excited in the pulse regime represent the main theme of the thesis. The discharge in the low-pressure plasma jet was studied by means of an electrostatic Langmuir probe, in the case of the planar magnetron, mass spectroscopy with energetic as well as time resolution was used. To understand the results achieved in the pulse generated plasma good knowledge of the basic continuous DC regime of the discharge excitation is essential. Therefore a considerable part of the thesis deals purely with the continuous DC discharge. In the case of the low- pressure plasma jet, the attention was focused also on the characteristic property of this plasma source, which is the flow from the jet.

Polyoxazolines are class of polymers which are suitable for medical applications because they have many interesting properties. These polymers are characterized by antibacterial properties so they can stop bacterial colonization of medical devices and significantly reduce the risk of infection. Furthermore, polyoxazolines are interesting for good biocompatibility. Basic topic of this diploma work is preparation of oxazoline-based thin films by plasma polymerization. Thin films were prepared by plasma polymerization from 2-methyl-2-oxazoline vapors in a nitrogen atmosphere in a dielectric barrier discharge. During the deposition was increased the substrate temperature. Polyoxazoline films were analyzed by several diagnostic methods. Physical and chemical properties of thin films were studied by SEM, AFM, FTIR by measuring contact angles and nanoindentation method. The films were found to be homogeneous, hydrophilic and have a higher nitrogen content. Furthermore, films showed viscoelastic properties. Polyoxazoline films were subjected to antibacterial and biocompatibility tests and the result showed, that films have antibacterial properties and support of viability cells viability.

This work deals generally with surface diagnostic and optical properties of thin layers which are created by plasma polymerization of hexamethyldisiloxane monomer. The influence of oxygen adittion on thin layers properties was studied, too. This polymer layers are commercially made to protect reflective layers in the headlights. Thin layers were made in deposition chamber AluMet 1800V at Zlin Precision Company. Teoretical part of this work deals with methods which are used for deposition of thin layers, mainly physical (PVD) and chemical (PECVD, CVD) depositions. The conditions which influenced plasma polymerization itself are discussed as well as, monomers which are used for plasma polymerization and stability of thin polymer layers. Also there are mentioned the most frequent plasma processes diagnostic methods applicable during the deposition (optical emission spectroscopy) and methods for thin layers diagnostic (wettability, UV-VIS and infrared spectroscopy). Spectrometer Jobin Yvon Triax 320 was used for emission spectra acquisition during the plasma deposition. There were analyzed only two spectra created at same conditions as power at 3 kW and monomer flow rate at 100 sccm; the first one was in pure monomer, the second was obtained with oxygen addition of 150 sccm into the monomer flow. There was not found any essential differences between these spectra in the range 300 nm to 800 nm. Besides the thin layers analyzes after their formation, the samples were exposed to common aging conditions with respect to their use. One third of the prepared samples was exposed by ultraviolet radiation for 48 hours (exposure power of 0.68 W.m-2 at 340 nm) and the other part of samples was inserted for four days into NaCl solution of 50 g.l-1. The surface properties of layers were studied by their contact angle with three liquids (water, diiodmethane, and glycerol) that allowed their surface energy calculation. Results of this measuring are as following: Oxygen addition decreased contact angle of water after exposure of UV radiation. If the highest flow rate of monomer was used and oxygen was added, NaCl degradation did not have any significant influence on contact angle to water. Optical properties of prepared thin films were characterized by UV-VIS spectroscopy. Optical properties were measured only for samples after deposition and samples that were exposed by ultraviolet radiation. Results showed that oxygen addition into the reacting mixture increased the light absorption in UV-VIS (300-800 nm). The absorption was significantly increased after exposure of ultraviolet radiation. With respect to the application of these thin layers is necessary to say that this influence is undesirable. On the other hand, absorption of thin layers deposited at 2 kW, without oxygen addition and flow rate of monomer at 125 sccm a 150 sccm was decreased. Results of this work can be useful for investigation and study of deposited thin layers. The most useful can be with another work which deals with plasma diagnostics during the deposition even more closely. Then it will be possible to adjust and predict properties of deposited layers.

The theoretical part of the thesis is focused on surface treatments, their evaluation from the point of view visual properties, plasma-enhanced chemical vapor deposition and analysis of thin layers prepared by plasma polymerization. The experimental part of the thesis deals with surface treatment of stainless steel AISI 304. Thin layers of pp-HMDSO (plasma-polymer) and of DLC are deposited on the steel´s surface for the purpose of preparing transparent layer, which protect steel´s surface against of making finger prints visible. As an objective method is chosen an immersion test in artificial sweat solution according to standard ČSN EN ISO 105-E04. Evaluation of the test is measured by a gloss-meter and by a colorimeter. Prepared layers are identificated by FTIR method.

This diploma thesis is focused on studying of the effect of the dielectric barrier discharge (DBD) on eucaryotic microorganisms. Plasma sterilization is considered to be an alternative method to conventional sterilization processes. Contrary to standard decontamination methods it doesn´t stress exposed material by heat, pressure and chemicals. Plasma acts on eucaryotic and procaryotic systems by means of synergy of three inactivation mechanisms. They are various reactive species, UV radiation and heat. The Aspergillus niger has been chosen as a bio-indicator enabling to evaluate the effect of plasma assisted microbial inactivation. Plasma was generated in dielectric barrier discharge (DBD) at atmospheric pressure. Nitrogen and argon were used as working gases, paper and PET foil were used as carrying media. The influence of various working conditions on the sterilization effect was studied. Namely it was the influence of plasma exposition time, plasma power density, the type of operating gas and type of supporting medium. The effect of UV radiation in combination with temperature, temperature and direct plasma were studied separately. According to our results the efficiency of DBD increases with plasma power density, resp. plasma exposition time. When comparing sterilization efficiency of nitrogen and argon operating at the same conditions, the higher sterilization effect was observed in argon. The influence of the carrying medium on sterilization effectiveness was proved. It was caused by the different structure of surface. It was found out, that in our experimental setup the active species are probably the main inactivation mechanism. The influence of temperature on inactivation of microorganisms was negligible. The combination of UV radiation and temperature reached the decontamination level about 2 orders. The discharge parameters were studied by means of optical emmision spectroscopy. Scanning electron microscopy enabled to evaluate possible damage of exposed materials through DBD.