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Surface topography of plasma polymers deposited on flat and fibrous substrates examined by atomic force microscopy
Kurakin, Yuriy ; Pálesch, Erik (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with the characterization of the morphology of thin films of plasma polymers, which were prepared from the monomer tetravinylsilane and deposited on planar silicon substrates and type E glass fibers. Plasma enhanced chemical vapor deposition (PE CVD) has been used as a method of thin films preparations. Characterization of the surface morphology was made by using atomic force microscopy (AFM), for which was prepared literature review at the theoretical part of this bachelor thesis. The collected data have been used for estimating dependence of surface topography in relation to the deposition conditions and the size of investigated area. Also have been suggested methods of the data interpretation for purposes of subsequent statistical analysis.
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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 analysis of a-CSi:H and a-CSiO:H films
Olivová, Lucie ; Franta, Daniel (referee) ; Čech, Vladimír (advisor)
Plasma-enhanced chemical vapor deposition is a promising technology for the preparation of materials in the form of thin films with controlled physical-chemical properties, which can be affected by changing input precursors or deposition conditions as needed. In this thesis, plasma nanotechnology was used to synthesize thin films on silicon wafers. Tetravinylsilane was chosen as a precursor for the synthesis of the films. In addition to pure tetravinylsilane, mixtures of tetravinylsilane with argon and mixtures of tetravinylsilane with oxygen were also used as input precursors for film deposition, in different proportions of the individual component in the deposition mixture. Using chemical analyses, specifically infrared spectroscopy, photoelectron spectroscopy and selected ion techniques, the chemical structure of the prepared films was examined in detail and the dependence of this structure on deposition conditions and input precursors was studied. This thesis confirms, that by changing effective power supplied to the plasma discharge and selecting different input precursors, it is possible to control chemical structure, and thus the properties of the prepared nanolayers.
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Surface morphology of a-CSi:H films prepared from tetravinylsilane in low-temperature plasma
Křípalová, Kristýna ; Pálesch, Erik (referee) ; Čech, Vladimír (advisor)
This bachelor thesis is focused on the surface morphology of a-CSi:H films. Films were prepared by plasma-enhanced chemical vapor deposition (PECVD) on silicon wafers using plasma discharge. Tetravinylsilane (TVS) precursor was used for deposition. The set of samples deposited at different effective power (2-150 W) and a thickness of about 0.6 µm was characterized to investigate their surface properties. Atomic force microscopy was used for characterization of surface morphology. Obtained results were used for evaluation of surface roughness and assessment of the effect of the film growth dynamics on the surface topography.
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Self-assembled layers based on silicon
Bábík, Adam ; Veselý, Michal (referee) ; Čech, Vladimír (advisor)
Thin film deposition, characterization and properties of self-assembled monolayers based on silicon were studied with emphasis on the SA monolayers deposited from vinyltriethoxysilane and vinyltrichlorsilane. The thesis is aimed at basic properties of the SA monolayer and explanation of its growth. Methods and techniques used for analysis of the monolayer were described as well. Contact angle measurements and an evaluation of the surface free energy are depicted in details. The deposited SA layers were observed with respect to their chemical composition and surface morphology by X-ray photoelectron spectroscopy (XPS), ellipsometry and atomic force microscopy (AFM).
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Fiber reinforcements for polymer composites
Knob, Antonín ; Grégr, Jan (referee) ; Čech, Vladimír (advisor)
The bachelor thesis is concerned with an influence of surface modification of fibrous reinforcements on mechanical properties at the fiber-matrix interface in fiber-reinforced polymer composites. Polyester resin was used as a matrix, glass and carbon fibers were the reinforcements. The composite sample consisted of polymer matrix in a form of cylindrical body placed on a bundle of fibers. Untreated fibers and fibers with a commercial sizing were used for fabrication of composite samples. The tensile test using a materials testing machine (Zwick) was employed to evaluate adhesion at the fiber-matrix interface.
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Characterization of a new deposition system for coating the fibers
Zvonek, Milan ; Salyk, Ota (referee) ; Čech, Vladimír (advisor)
Cieľom bakalárskej práce je charakterizácia depozičného systému na výrobu tenkých vrstiev. Teoretická časť je zameraná na literárnu rešerš o plazme, plazmovej polymerácií, tenkých vrstvách a ich analýzu pomocou infračervenej spektroskopie a spektroskopickej elipsometrie. Experimentálna časť popisuje použité materiály a aparaturu použitú na prípravu tenkých vrstiev pomocou plazmovej polymerácie. Posledná časť popisuje výsledky merania depozícií tenkých vrstiev a ich vyhodnotenie vzhľadom na depozičné podmienky.
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Surface topography of a-CSi:H films deposited by continuous wave PECVD
Blažková, Naďa ; Pálesch, Erik (referee) ; Čech, Vladimír (advisor)
The thesis describes surface topography of a-CSi:H films deposited by continuous wave plasma enhanced chemical vapor deposition (PECVD) based on tetravinylsilane monomer (TVS). Thin films are completely used in many fields of modern technologies and their physical and mechanical properties are affected by thin film preparation techniques. In this thesis the thin films were deposited by PECVD method on silicon wafers with the pure TVS monomer. Deposited samples were topographically described and analyzed using atomic force microscopy (AFM). The main characteristics which were described are RMS roughness, autocorrelation function and a size distribution of grains on the thin film surface. Analysis was realized with two sets of samples with different powers and thickness. The main results were statistically evaluated like a mixture of object on the surface prepared in different deposition conditions.
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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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Synthesis of low-crosslinked polymers by plasma polymerization
Kuchtová, Štěpánka ; Bránecký, Martin (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with plasma enhanced chemical vapour deposition (PECVD), specifically plasma polymerisation, which has been used for the synthesis of low density crosslinked polymer thin films. Organosilicon thin films were deposited on a silicon substrate by radio frequency (RF) capacitively coupled plasma in a deposition chamber. Spectroscopic ellipsometry was used to determine the layer thickness and its optical properties. The chemical structure of the layers was investigated by Fourier transform infrared spectroscopy and the mechanical properties were investigated by nanoindentation. The effect of power and self-bias (USB) on the chemical structure, mechanical and optical properties of the as-prepared layers, which are related to the crosslinking density, was investigated in the context of achieving low crosslinking density of the material. Low crosslinked plasma polymers were synthesized at a self-bias level of 1 V, which corresponds to an approximate RF power of 0,1 W. This material can be characterized by a density of 1, 2 g·cm-3 an elastic modulus of 4 GPa, a hardness of 0,04 GPa and a refractive index of 1.53 at 633 nm (He-Ne laser wavelength). Infrared spectroscopy confirmed that this plasma polymer is composed of a carbon network with fewer embedded silicon atoms and, in particular, the highest concentration of vinyl groups compared to plasma polymers prepared at higher powers.
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