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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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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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Polymer layers prepared on the basis of 2-methyl-2-oxazoline by plasmachemical method and their diagnostics
Podzemná, Daniela ; Kozáková, Zdenka (referee) ; Mazánková, Věra (advisor)
The main topic of this bachelor thesis was preparation of 2-methyl-2-oxazoline-based thin polymer layers. These layers were prepared by plasma polymerization in a dielectric barrier discharge in an inert nitrogen atmosphere. In experimental part polyoxazoline layers were characterized using several diagnostic methods. The first one was study of layers surface using scanning electron microscopy, next was determination of contact angles and subsequent determination of free surface energy. Antibacterial properties were also investigated by antibacterial tests using a bacterial culture of Staphylococcus epidermidis.
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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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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 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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Plasmachemical preparation of polymer layers based on 2-ethyl-2-oxazoline and their diagnostics
Podzemná, Erika ; Menčík, Přemysl (referee) ; Mazánková, Věra (advisor)
The bachelor’s thesis deals with deposition of thin polymer layers on 2-ethyl-2-oxazolin basis in a dielectric barrier discharge in a nitrogen atmosphere. Polyoxazolines are characterized by good antibacterial effects in general, which make them a suitable material for medical applications. After preparing of the layers. Their properties were studied using three methods. The first were antibacterial tests, which unfortunately did not confirm the above written properties. Furthermore, the free surface energy of the layers, from which it could be inferred that the surfaces were hydrophilic, was determined by measuring contact angles. The scanning electron microscopy showed the surface of the layers as well as the elemental composition thanks to the connected X-ray detector.
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