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Macromolecular avenues for the creation of bio-inspired hierarchically structured surfaces
Wang, Yu-Min ; Pop-Georgievski, Ognen (advisor) ; Kostka, Libor (referee) ; Sedláček, Ondřej (referee)
Biomedical applications often rely on surface adherent architectures such as polymer brushes to prevent adverse nonspecific interactions between materials used in biomedicine and contacting biological fluids. Commonly, "grafting-to" (GT) and "grafting-from" (GF) methods are used to attain the polymer brush architecture on various surfaces. This study investigates the grafting density and antifouling effectiveness of poly[N-(2-hydroxypropyl) methacrylamide] (poly(HPMA)) brushes synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization, employing both GT and GF techniques. To determine the molar masses of solution-born and GF poly(HPMA), size exclusion chromatography (SEC) equipped with multiple angle laser light scattering (MALS) and atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) were combined and thoroughly used. Furthermore, the impact of solvent effects on polymer brush propagation kinetics during the concomitant surface-initiated- (SI-) RAFT process between surface and solution was investigated. Experimental findings revealed discrepancies between GF and solution-born poly(HPMA) chains. Notably, solvent composition influenced both the propagation rate and the inferred grafting density of surface-grafted poly(HPMA) due to variations in...
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Preparation of nanoparticles and their use as contrast agents for in vivo imaging.
Odehnalová, Nikola ; Kratochvílová, Irena (referee) ; Turánek,, Jaroslav (advisor)
This diploma thesis deals with the optimalization of synthesis of gold nanoparticles and their surface modification allowing their use as contrast agents for in vivo imaging by CT. Gold nanoparticles were prepared by the Turkevich method and characterized by TEM, DLS, MADLS and UV -Vis. Their surface was functionalized with polyethylene glycol containing a thiol group forming a bond with the Au atoms in the surface of gold nanoparticles. The terminal end of the polymer was methylated or containing an aminooxy group forming an orthogonal bond with hyaluronic acid using click-chemistry. The eligibility for in vivo application of the prepared nanoparticles was verified with stability and cytotoxicity tests. The nanoparticles modified by methylated polyethyleneglycol were injected intravenously into a mouse and their application potential as contrast agents were verified by CT.
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Noise, Transport and Structural Properties of High Energy Radiation Detectors Based on CdTe
Šik, Ondřej ; Lazar, Josef (referee) ; Navrátil, Vladislav (referee) ; Grmela, Lubomír (advisor)
Poptávka ze strany vesmírného výzkumu, zdravotnictví a bezpečnostního průmyslu způsobila v posledních letech zvýšený zájem o vývoj materiálů pro detekci a zobrazování vysokoenergetického záření. CdTe a jeho slitina CdZnTe. jsou polovodiče umožnují detekci záření o energiích v rozsahu 10 keV až 500 keV. Šířka zakázaného pásma u CdTe / CdZnTe je 1.46 -1.6 eV, což umožňuje produkci krystalů o vysoké rezistivitě (10^10-10^11 cm), která je dostačující pro použití CdTe / CdZnTe při pokojové teplotě. V mé práci byly zkoumány detektory CdTe/CdZnTe v různých stádiích jejich poruchovosti. Byly použity velmi kvalitní spektroskopické detektory, materiál s nižší rezistivitou a výraznou polarizací, detektory s asymetrií elektrických parametrů kontaktů a teplotně degenerované vzorky. Z výsledků analýzy nízkofrekvenčního šumu je patrný obecný závěr, že zvýšená koncentrace defektů způsobí změnu povahy původně monotónního spektra typu 1/f na spektrum s výrazným vlivem generačně-rekombinačních procesů. Další výrazná vlastnost degenerovaných detektorů a detektorů nižší kvality je nárůst spektrální hustoty šumu typu 1/f se vzrůstajícím napájecím napětí se směrnicí výrazně vyšší než 2. Strukturální a chemické analýzy poukázaly, že teplotní generace detektorů způsobuje difuzi kovu použitého při kontaktování a stopových prvků hlouběji do objemu krystalu. Část mé práce je věnována modifikaci povrchu svazkem argonových iontů a jejímu vlivu na chemické složení a morfologii povrchu.
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Plasma Chemical Surface Treatment of Polymeric Materials for Biomedical Applications
Mikušková, Radka ; Kozáková, Zdenka (referee) ; Krčma, František (advisor)
The theoretical part of bacalor thesis summarizes a plasma application for surface modification of materials used for biomedical applications. The main focus is on polymeric materials. Practical part focuses on specific surface modifications. An aim is to obtain from the initially hydrophobic surface hydrophilic by plasma chemical surface treatment and to optimize the method. Hydrophilicity is achieved by treating the sample in low temperature low pressure plasma generated in air based gaseous mixtures. The surface treatment efficiency is characterizad by water leak through the material. Structural changes of material surface are confirmed by X-ray photoelectron spectroscopy.
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Optimization of thin films of metal oxide materials
Vítek, Jiří ; Šimonová, Lucie (referee) ; Šubarda, Jiří (advisor)
This thesis is focused on the description of the method of reactive sputtering of thin films. Currently, there are many ways how to create thin films and there are many applications of thin films in various industrial sectors. In this paper at the first are listed the issue of thin films, followed by an overview of the deposition techniques and of the chemical analysis of deposited thin films. It also describes the four-point measurement method of sheet resistance, mechanical test of adhesion and optical properties. At the end of the theoretical part are described the material composition of the deposited films. The goal of the practical part is to optimize the deposition process of the mixed layer of indium tin oxide (In2O3: SnO2) and contribute to the overall understanding of the influence of annealing on the layer. There were created six series of samples with that applied layers. First, the work focused on examining of the influence of annealing on the throughput in the whole measuring range, and then comparing the series due to the transmittance in the visible light spectrum. Furthermore were compared the value of sheet resistance of unannealed and subsequently annealed samples.
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Unconventional preparation technology of bulk material from Mg
Horálek, Matyáš ; Hasoňová, Michaela (referee) ; Březina, Matěj (advisor)
Topic of the bachelor's thesis is the procedure of preparation and processing of bulk magnesium powder by unconventional technologies. Bulk materials were evaluated from the point of porosity, microstructure and physically-mechanical properties in correlation with changes of parameters during preparation. Furthemore the influence of chosen processing parameters of electron beam was evaluated from structural properties and depth of the affected material. The outcome of this work is focused on study and optimalization of parameters during preparation and processing of bulk material.
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Hybrid composite based on dental matrix
Almásyová, Zuzana ; Bystřický, Zdeněk (referee) ; Přikryl, Radek (advisor)
This bachelor´s thesis deals with the study of the effect of alumina fillers addition on mechanical properities of experimental composite based dimethacrylate matrix. Important properities and aspects of particle composite, composite mechanics and surface treatments methods were described in the theoretical section of this work. As a studied system was dimethacrylate matrix with micro-filler in form of barium glass and nano-filler in form of alumina. The filler was modified by two silanization methods. Surface treatment of the filler was studied by termogravimetry and infrared spectroscopy. Morphology of fracture areas was examined using scanning electron microscopy with the aim to characterize dispersion of particles in the matrix. Mechanical properties of prepared composite materials were established by the testing of the flexural properties. The best silanization method of particular filler was determined. The addition of alumina had a negative effect on the resulting mechanical properties of prepared composite.
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Application of Surface Treatment on Hand Tools
Vraspírová, Eva ; Klakurková, Lenka (referee) ; Doležal, Pavel (advisor)
Bachelor's thesis deals with problems of materials, which are used to production of hand tools and implements. The theoretical part is focused on tool steels, their mechanical and technological characteristics and to their heat processing. Below there are well-arranged and described surface modification, which are applied to materials nowadays. The next part is focused on modern technology of surface modification, which are applied to hand tools. The research is mainly focused on technology of production of bits by company Wera Werk Ltd, which is deal with production and distribution of hand tightening tools, such as screwdrivers, angular keys, plug keys, bits and torque tools. Attention is also paid to technology of surface modification, e.g. based on zinc phosphate, nickel, nickel-gold and nickel-diamond-gold, used for these tools and to problems of painting. To elements interaction study light microscopy, the hardness measurement by Vickers and Brinell and scanning electron microscopy equipped by energy dispersive microanalyses.
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Plasma surface modification of powder fillers
Štulrajterová, Lujza ; Bystřický, Zdeněk (referee) ; Přikryl, Radek (advisor)
This bachelor’s thesis deals with the study of particulate-filled composite materials and the influence of filler surface modifications on the properties of the composite. Important aspects of particulate fillers, used fillers and possible surface treatments were characterized in the theoretical section of this work. Dimethacrylate matrix with halloysite nanotubes as filler was chosen as a studied system. The filler was modified by low-temperature plasma under low pressure and by silanization. Surface of the modified filler was studied by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Particle size distribution was measured by photon cross-correlation spectroscopy and dynamic light scattering (DLS). Mechanical properties of prepared particulate composites were established by the testing of the flexural properties. Fracture areas were analyzed by using scanning electron microscopy (SEM). The results showed no effects of the plasma treatment on the mechanical properties. Silane treatment of the filler surface illustrated improvement of the composite material strength.
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