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Surface topography and mechanical properties of thin films on tetravinylsilane basis
Plichta, Tomáš ; Klapetek, Petr (referee) ; Čech, Vladimír (advisor)
Proposed diploma thesis is focused on preparation and characterization of the plasma polymer thin films based on tetravinylsilane monomer (TVS). Plasma enhanced chemical vapour deposition (PECVD) method involving pulse and continual plasma discharge modes were used for thin film deposition on silicon wafer pieces. Reactive plasma composition was containing pure TVS or mixtures of TVS and argon or oxygen gas. Atomic force microscopy was used for surface topography and roughness characterization. Cyclic nanoindentation was involved to measurements to determine the Young’s modulus and hardness of prepared films and scratch test was performed to evaluate the degree of adhesion. Special attention was drawn to the characterization of films with a Young’s modulus below 10 GPa. Tip geometry of indenter influence on scratch test was also commented. Surface and mechanical properties of thin films in relation to the deposition conditions were correlated to the obtained results and final analysis of deposition conditions influence is proposed.
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Fabrication of well defined nanoporous structures with application in membrane sensing
Fabianová, Kateřina ; Édes, Zoltán (referee) ; Sadílek, Jakub (advisor)
Theme of this bachelor thesis is focused on preparation of the metal nanomenhir structures situated in highly oriented matrix of silicon nitride nanopores based plasmonic biosensor. Porous structures were prepared by reactive ion etching of silicon nitride film using electron beam lithography prepared temporary mask as a template. Deposition of metals was handled by evaporation and magnetron sputtering and results was compared. Finally, this work assumes reached results including successful approach of sensor preparation without contamination of surrounding surface by heavy metal ions.
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Adhesion of plasma polymer films deposited from tetravinylsilane monomer
Plichta, Tomáš ; Salyk, Ota (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with the characterization of thin films of plasma polymers prepared from monomers of tetravinylsilane (TVS) and deposited on planar silicon substrates. Plasma enhanced chemical vapor deposition (PE CVD) was used as a method of thin films preparation. Three power series were prepared from pure TVS and two mixtures TVS with argon and oxygen. The main characterization methods were scratch tests and atomic force microscopy (AFM) is used to assess the adhesion degree of the layers and topography of scratches. To assess the characteristics and context the layer thickness was measured by spectroscopic ellipsometry (ELL) and elastic modulus using nanoindentation. The collected data were used to assess the reproducibility of the results with the regard to the purity of substrates and adhesion layers, depending on the deposition conditions and layers aging.
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Reducing friction losses of piston rings
Csintalan, Radoslav ; Novotný, Pavel (referee) ; Svída, David (advisor)
This diploma thesis deals with the possibilities of reducing the friction losses of the first sealing piston rings of the VW Group 1.5 TSI, 110kW engine. The first part of the thesis theoretically deals with the issue of piston rings in terms of their classification. Reduction of friction losses is ensured by PVD and PECVD coating technology. The second part of the thesis describes the production of coated piston rings. Measurements are performed on the created coatings, which are compared and evaluated in the conclusion at the end of the thesis.
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Reducing friction losses of piston rings
Csintalan, Radoslav ; Novotný, Pavel (referee) ; Svída, David (advisor)
This diploma thesis deals with the possibilities of reducing the friction losses of the first sealing piston rings of the VW Group 1.5 TSI, 110kW engine. The first part of the thesis theoretically deals with the issue of piston rings in terms of their classification. Reduction of friction losses is ensured by PVD and PECVD coating technology. The second part of the thesis describes the production of coated piston rings. Measurements are performed on the created coatings, which are compared and evaluated in the conclusion at the end of the thesis.
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Biomedical applications of polycaprolactone nanofibrous mats
Dvořák, Pavel ; Přibyl,, Jan (referee) ; Zajíčková, Lenka (advisor)
The diploma thesis deals with the treatment of polycaprolactone (PCL) nanofibers. PCL fibers were subjected to the deposition of plasma amine polymers in a low pressure pulsed radiofrequency capacitively coupled discharge using cyclopropylamine monomer (CPA). Collagen as an extracellular matrix (ECM) protein was immobilized and cell proliferation on the modified nanofiber surface was monitored. Untreated PCL fibers were also subjected to the deposition of an antibacterial copper layer, and the fibers were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDX).
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Surface and mechanical properties of a-CSi:H and a-CSiO:H films
Plichta, Tomáš ; Shukurov, Andrey (referee) ; Klapetek, Petr (referee) ; Čech, Vladimír (advisor)
The dissertation thesis deals with the preparation and characterisation of a-CSi:H and a CSiO:H thin films prepared using the process of plasma enhanced chemical vapour deposition (PECVD). Tetravinylsilane (TVS) and its mixtures with argon and oxygen were used to deposit films on both planar substrates and fibre bundles. Main characterisation techniques were employed to study the topography of films, namely atomic force microscopy (AFM). Their mechanical properties were studied through nanoindentation; the nanoscratch test was used to assess the film adhesion to the substrate. Other analysed properties were internal stress and friction coefficient. The particular attention was paid to the work of adhesion and its determination. This knowledge was further applied to the preparation of surface treatments of glass fibres and, subsequently, polymer composites. Those were tested using the push-out test and the short beam shear test. Based on the results, the effects of deposition conditions and the relationships between the studied properties and quantities were determined.
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Shear strength of the fiber-reinforced polymer composite
Jurko, Michal ; Knob, Antonín (referee) ; Čech, Vladimír (advisor)
The diploma thesis deals with the study of Inter-Laminar Shear Strength (ILSS) of polymer composites, based on unsaturated polyester resin with unidirectionally oriented basalt or glass fibers. The basis of the experimental part is the preparation of composite samples with different types of surface treatment of a fibers (a reinforcement) as well as the surface treatment itself. The untreated, the commercially treated fibers and the plasmatreated fibers used as reinforcement in the polymer composites were analysed by a short beam shear test and their ILSS was determined. The effect of various deposition conditions during Plasma-Enhanced Chemical Vapour Deposition (PECVD) on the value of ILSS of the composite with originally unsized glass or basalt fibers was studied. The impact of aging on the interlaminar shear strength of the composites was investigated for commercially treated glass fibers. The Scanning Electron Microscopy (SEM) is also used in the thesis together with the Energy Dispersive Spectroscopy (EDS). Based on all the results a proposal was made to correct and improve the deposition conditions and thus improve the interphase to achieve the required shear properties of polymer composites.
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Infrared spectroscopy of thin films
Kiss, Andrej ; Čáslavský, Josef (referee) ; Čech, Vladimír (advisor)
Cílem této bakalářské práce je literární rešerše v oblasti tenkých vrstev, plazmochemické depozice z plynné fáze a infračervené spektroskopie Fourierovou transformací, a měření infračervených spekter tenkých vrstev a charakterizace jejich chemické struktury na základě změřených spekter. Pomocí infračervené spektroskopie Fourierovou transformací bylo měřeno pět vzorků tenkých polymerních vrstev z tetravinylsilanu, vytvořených na křemíkovém substrátu pomocí plazmochemické depozice z plynné fázi s efektivním výkonem v rozmezí od 2 W do 150 W. Měření odhalilo chemické vazby přítomné ve vzorcích a jak se struktura měnila s měnící se efektivním výkonem. Snížení absorpčních pásů s přítomností vodíku naznačuje zvýšení zesítění se zvýšeným efektivním výkonem. Také snížení absorpčních pásů s přítomností křemíku poskytuje důkaz pro zvýšení poměru C/Si. Tyto výsledky nám pomáhají porozumět charakteristikám těchto tenkých vrstev a přispívají k pochopení procesu plazmochemické depozice z plynné fáze.
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