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Adhesion of a-SiOC:H films on planar substrates
Lepcio, Petr ; Salyk, Ota (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with preparation of thin films of plasma polymers prepared by plasma-enhanced chemical vapor deposition. Tetravinylsilane was used as a monomer. Two sets of samples were prepared. Samples of the first set were prepared at different effective powers from pure tetravinylsilane and samples of the second set were prepared from deposition mixture of tetravinylsilane with different oxygen content at constant effective power. The film thickness was evaluated by spectroscopic ellipsometry and chemical structure by infrared spectroscopy. A scratch test was used to determine adhesion characterized by the critical normal load. An appearance of performed scratches was obtained by atomic force microscopy (AFM). Film adhesion influenced by the effective power and oxygen content in deposition mixture was discussed based on the received data.
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Design of a device for scratch tests
Brandejs, Petr ; Otáhal, Alexandr (referee) ; Skácel, Josef (advisor)
This thesis deals with designing a scratch tester. Theoretical part introduces scratch testing, with focus mainly on testing adhesion and layer toughness in microelectronics. Second chapter deals with research of commercially available scratch tester parameters. Based on the findings, construction, and electronics of a device capable of performing scratch tests with required parameters were designed. In the end, a few scratch tests were performed to show capabilities of the device.
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Influence of Zinc Coating Morphology on Limit Conditions Formability of Thin Sheet Metal
Císařová, Michaela ; Suchánek, Jan (referee) ; Rusz, Stanislav (referee) ; Dvořák, Milan (advisor)
The doctor thesis deals about the influence of zinc coating morphology on limit conditions formability of a thin sheet metal. In the introduction of the thesis is discusesed about current problems searching the most suitable morphology of the steel sheet metals, a method of appliing to the zinc sheet metal. The hot dip zinc coating is discussed in next chapter, the topical knowledges about the influence of the individual factors have some effect to coat calibre and quality. In literary researchs are discussed the concrete technological tests of zinc coating to harder sheet metal forming, the theory of the bend and the basic theory of pressing sheet metal. In following chapter is devoted interpretation selected technological tests, according to that is described behaviour, characteristics, influence of zinc coating formability of basic material and his morphology.
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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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Deposition and analysis of DLC thin films
Rudolf, Miroslav ; Čech, Vladimír (referee) ; Šikola, Tomáš (advisor)
Diplomová práce nastiňuje problémy spojené s výrobou a analýzou tenkých vrstev DLC:H. Tyto vrstvy jsou ve středu zájmu mnoha vědeckých pracovníků již po několik desetiletí. V současné době existuje mnoho technik pro přípravu a analýzu. Příprava DLC vrstev má zásadní vliv na jejich vlastnosti a možnosti použití. Je zde mnoho kritérií jak vrstvy posuzovat. V této práci jsou studovány vlastnosti DLC:H vrstev připravených na substrát krystalického křemíku metodou RF-PECVD a následně jsou studovány mechanické, tribologické a optické vlastnosti. Jsou zde využity techniky jako XPS, Ramanova spektroskopie, reflektometrie, měření tvrdosti a adheze. Část práce se zabývá modelováním DLC z prvních principů. Pro tento účel je využito prvoprincipiálního programu Abinit který je šířen pod GPL. Je studována otázka přípravy vstupních dat s ohledem na konvergenci výsledků. Pozornost je také věnována výpočtu vibračních spekter ve středu Brillouinovy zóny ( bod) a celkové hustotě elektronových stavů clusteru DLC v supercele tvaru krychle. Tyto výsledky mohou být porovnány s experimentálně získanými daty z Ramanovy spektroskopie, respektive z XPS spektra valenčního pásu
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Hardness and scratch resistance measurement using universal tribometer
Urbášek, Jan ; Galas, Radovan (referee) ; Omasta, Milan (advisor)
This bachelor thesis deals with a hardness and scratch resistance measurement. These tests are normally performed using special devices. From a design point of view, these tests can also be performed using universal tribometers, but they do not have implemented tools for subsequent measurement evaluation. The main goal of the work was to develop a methodical procedure including evaluation of these tests. The methodological procedures were subsequently verified by several experiments.
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Study of Thin-Film Surfaces
Trivedi, Rutul Rajendra ; Fejfar, Antonín (referee) ; Klapetek, Petr (referee) ; Šikola, Tomáš (referee) ; Čech, Vladimír (advisor)
Disertační práce se zabývá studiem povrchových vlastností jedno a vícevrstvých filmů deponovaných z vinyltriethoxysilanových a tetravinylsilanových monomerů. Zabývá se také charakterizací adheze jednovrstvých filmů z tetravinylsilanu. Plazmaticky polymerizované tenké vrstvy byly připraveny na leštěných křemíkových substrátech pomocí plazmové depozice z plynné fáze za ustálených podmínek. Povrchové vlastnosti vrstev byly charakterizovány pomocí různých metod rastrovací sondové mikroskopie a nanoindentačních technik jako je konvenční a cyklická nanoindentace. Vrypový test byl použit pro charakterizaci vlastností adheze vrstev. Jednovrstvé filmy připravené za různých depozičních podmínek byly charakterizovány s ohledem na povrchové morfologie a mechanické vlastností (modul pružnosti, tvrdost). Výsledky morfologie povrchu, analýzy zrn, nanoindentace, analýzy konečných prvků a modulů mapování pomohly rozlišit hybridní charakter filmů, které byly deponovány při vyšších výkonech RF-výboje. Nový přístup byl použit v povrchové charakterizaci vícevrstvého filmu pomocí rastrovací sondové mikroskopie a nanoindentace. Adhezívní chování plazmaticky polymerizovaných vrstev různých mechanických vlastností a tloušťek bylo analyzováno pomocí normálních a laterálních síl, koeficientu tření, a snímků vrypů získaných pomocí mikroskopie atomárních sil.
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Polyethylenterepthalate Copper Plating for Conductive Structures Realisation
Chmela, Ondřej ; Zatloukal, Miroslav (referee) ; Starý, Jiří (advisor)
The content of this master’s thesis are methods of pretreatment and coating of the surface of PET to produce conductive copper structure and quality control. Thesis also includes theoretical analysis of these methods. Physical and chemical techniques of surface pretreatment methods are discussed in the theoretical part as well as methods making surface of substrate conductive, the subsequent galvanic copper plating and quality control of coating and testing of the adhesion between layers. The experimental part focuses on two methods of the polymer material surface pretreatments. The properties of these pretreatments were evaluated by using the atomic force microscopy and detection of surface energy by wetting and contact angle measurements. The surface is making conductive with cathode sputtering and electrochemical coating of copper. Adhesion of layers is tested mainly with scratch test and other methods. The results of these sub-operations are used for the realization of multi-layer conductive structures.
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Surface and Mechanical Properties of Thin Films
Pálesch, Erik ; Klapetek, Petr (referee) ; Skuhurov,, Andrey (referee) ; Čech, Vladimír (advisor)
The doctoral thesis deals with the study of morphology and mechanical properties of thin plasma polymer films based on tetravinylsilane monomer and its mixtures with oxygen and argon. Thin films were prepared by plasma-enhanced chemical vapour deposition on silicon and glass substrates. Atomic force microscopy was used for characterization of thin film surface and for depiction of composite interphase with functional interlayer. Mechanical properties of thin films, namely Young’s modulus and hardness, were studied by cyclic nanoindentation technique. Nanoindentation device was also used to carry out scratch test, which was helpful to describe adhesion of films to substrate. In this thesis the influence of deposition conditions on surface and mechanical properties of thin films prepared in continual and pulse wave on planar substrates is discussed. Also, the suitability of few atomic force microscopy techniques for depiction of composite interphase was reviewed.
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Preparation and characterization of modern wound covers
Balášová, Patricie ; Pernicová, Iva (referee) ; Skoumalová, Petra (advisor)
This diploma thesis is focused on the study of bioactive wound dressings. During the thesis, hydrogel, lyophilized and nanofiber wound dressings were prepared. Hydrogel and lyophilized wound dressings were prepared on basis of two polysaccharides – alginate and chitosan. Nanofiber wound dressings were prepared by spinning polyhydroxybutyrate. All prepared wound dressings were enriched with bioactive substances, which represented analgesics (ibuprofen), antibiotics (ampicillin) and enzymes (collagenase). Into hydrogel and lyophilized wound dressings were all the mentioned active substances incorporated, whereas nanofiber wound dressings were only with ibuprofen and ampicillin prepared. The theoretical part deals with the anatomy and function of human skin. There was explained the process of wound healing and also there were introduced available modern wound dressings. The next chapter of the theoretical part deals with materials for preparing wound dressings (alginate, chitosan, polyhydroxybutyrate) and with active substances, which were used during the experimental part of this thesis. In the theoretical part, the methods of preparation of nanofiber wound dressings and also the methods of cytotoxicity testing used in this work were presented. The first part of the experimental part of this thesis was focused on preparing already mentioned wound dressings. Then, their morphological changes over time and also the gradual release of incorporated active substances into the model environment were monitored. The gradual release of ampicillin was monitored not only spectrophotometrically, but also by ultra-high-performance chromatography. In wound dressings, in which collagenase was incorporated, was also the final proteolytic activity of this enzyme monitored. The effect of the active substances was observed on three selected microorganisms: Escherichia coli, Staphylococcus epidermidis and Candida glabrata. The cytotoxic effect of the active substances on the human keratinocyte cell line was monitored by MTT test and LDH test. A test for monitoring the rate of wound healing – a scratch test – was also performed.
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