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Deposition and characterization of polymer layers prepared from 2-Methyl-2-oxazoline
Tomečková, Klára ; Čech,, Jan (referee) ; Mazánková, Věra (advisor)
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.
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Plasma surface modification of glass fibers and its optimization
Širjovová, Veronika ; Knob, Antonín (referee) ; Čech, Vladimír (advisor)
Diploma thesis deals with glass fiber surface modification using plasma-enhanced chemical vapor deposition in order to prepare functional interface that enhances the properties of polymer composites. The effect of deposition conditions on shear strength was observed with respect to the chemical composition of the deposited film. Thin films were deposited on planar substrates and fibers using monomer tetravinylsilane in a mixture with oxygen at selected power of plasma discharge. Chemical composition of prepared material was analyzed by infrared spectroscopy. Planar substrate film adhesion was measured using the scratch test. The composite sample was prepared by embedding the surface modified fibers in unsaturated polyester resin, followed by the curing process. The cured composite sample underwent the short beam shear test.
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Chemical structure of silicon-based thin films
Olivová, Lucie ; Franta, Daniel (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with the characterization and preparation of thin polymer films deposited on silicon wafers by plasma-enhanced chemical vapour deposition. The main part of the work is background research in the field of plasma polymerization and infrared spectroscopy. Thin polymer films based on tetravinylsilane and tetravinylsilane with the addition of mixed gas (argon) were prepared in the experimental part. The prepared thin films of plasma polymers were characterized by the selected spectroscopic technique - infrared spectroscopy. Based on the evaluation of transmission infrared spectra, the chemical structure of the deposited polymer films was determined. The determined chemical structures of the prepared films were observed with respect to the deposition conditions and hence the possibility to prepare tailored films for a variety of applications.
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In-flight modification of nanoparticles by chemically active plasma
Libenská, Hana ; Hanuš, Jan (advisor) ; Kohout, Jaroslav (referee)
Title: In-flight modification of nanoparticles by chemically active plasma Author: Hana Libenská Department: Department of Macromolecular Physics Supervisor: Mgr. Jan Hanuš Ph.D., Department of Macromolecular Physics Abstract: This diploma thesis is focused on a fabrication of the iron nanoparticles using the gas aggregation source with a planar magnetron and their in flight modification by chemically active plasma. The modification of the nanoparticles is based on a radiofrequency glow discharge, that takes place right after the nanoparticles flew out of the gas aggregation source. Nanoparticles are prepared in an argon atmosphere in which a small amount of the n-hexane has been admixed. This n-hexane impurity caused an increase in a deposition rate and higher time stability. The modification takes place in a glow discharge containing a pure argon, or in the mixtures of argon with n-hexane, ethylendiamine, hydrogen or nitrogen. Prepared nanoparticles were characterized using the X-ray photoelectron spectroscopy, scanning and transmission electron microscopy, X-ray diffraction and other techniques. The main aim of this work was to study the influence of the additional discharge on the iron nanoparticles. The chemical composition of the nanoparticles was measured immediatelly after their deposition without...
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Surface modification by means of metallic and polymeric nanoparticles
Steinhartová, Tereza ; Hanuš, Jan (advisor) ; Matoušek, Jindřich (referee)
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)
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High Performance Polymer Composites
Bábík, Adam ; Lapčík,, Lubomír (referee) ; Prokeš, Jan (referee) ; Čech, Vladimír (advisor)
High performance polymer composites are materials with emphasis on specific chemical and mechanical properties due to their broad scope of applications. The main advantages are high strenght and toughness in comparison with their low weight and density. An increased adhesion at composite interfaces is important to ensure excellent composite properties. Bundles of glass fibers were coated by plasma-polymerised interlayers of tetravinylsilane (pp-TVS) of different thicknesses and at different effective powers. The prepared interlayers of pp-TVS were analyzed to evaluate chemical composition (RBS, FTIR, XPS) and mechanical properties (NI-AFM). Microindentation test and fiber-bundle pull-out test were used to determine the interfacial shear strenght.
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Deposition and optical properties of thin films and layered structures by PECVD
Kucharčík, Jan ; Boušek, Jaroslav (referee) ; Čech, Vladimír (advisor)
Thesis in theoretical part is focused on the principle of spectroscopic ellipsometry and formation of thin films by plasma-enhanced chemical vapor deposition (PECVD). In the experimental part we describe the deposition system, ellipsometer and mathematical evaluation of ellipsometric data, materials used for film formation and processing of the samples. Single-layer and multilayer structures of polymeric materials were prepared. We revealed that the optical properties of thin films are independent of film thickness. We also described the effect of the effective power and deposition gas mixture on optical properties of thin films.
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Plasma-enhanced chemicial vapor deposition
Žák, Luboš ; Salyk, Ota (referee) ; Čech, Vladimír (advisor)
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.
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Study of plasma species by mass spectroscopy
Bureš, Michal ; Čáslavský, Josef (referee) ; Čech, Vladimír (advisor)
Plasma polymer films of tetravinylsilane and mixture of tetravinylsilane and oxygen gas were deposited on silicon wafers. Oxygen gas was mixed in tetravinylsilane to improve the compatibility of thin films on glass substrates. Mass spectroscopy was employed during the cleaning of the deposition chamber to check residual gases and process gases, during plasma deposition to monitor neutral plasma species and to follow plasma stability.
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