Surface modification is an extensively researched approach in order to overcomethe limitations, and improve the performance of orthopedic and dental implants. It is atthe surface of the implant materials that the initial interactions of tissues or body fluidstake place. Therefore, surface properties of biomaterials are the important factors that cancontrol these biological responses. Molecular imprinting is a surface modificationtechnique that creates specific recognition sites on the surface of biomaterials. Todevelop the recognition sites, a functional monomer is assembled with templatebiomolecule and then crosslinked. After removal of the template, the surface can rebindthe molecules. Therefore, desired reactions can be initiated at the interface between tissueand implants by modifying surfaces to selectively bind certain types of biomolecules,such as proteins. The objective of this project was to observe the potential of molecularimprinting technique for creating biomaterials that can recognize specific biomolecules.Fluorescently labeled lysozyme or RNase A was used as a template biomolecule and theprotein-imprinted scaffolds were fabricated by sol-gel processing. To interpret the densityof binding sites created, the quantity of surface-accessible protein was determined. Theamount of protein available on the surface was proportional to the amount loaded.Protein-imprinted scaffolds were evaluated for their ability to selectively recognize thetemplate biomolecule. Further, for these selectivity studies, a combination of theimprinted protein and a competitor protein were rebound to the polysiloxane scaffolds.The template protein rebound to the surface was measured more than twice as much ascompetitor. These scaffolds were then tested to understand their interaction with cells.The results of DNA and alkaline phosphatase activities indicate that the scaffolds thusdeveloped support growth and adhesion of osteoblastic cells. These initial selectivity andcytocompatibility studies show the potential of molecular-imprinted polysiloxanescaffolds to be used as tissue engineered materials for stable and controlled interactions atthe tissue-implant interface.

Molecular imprinting, a common method used in separations and chromatography to isolate specific molecules via surface binding, has been adapted for applications in biomaterials and related sciences. The objective of this study was to determine the effectiveness of different approaches to molecular imprinting by testing for preferential binding of protein on polysiloxane scaffold surfaces. To test preferential rebinding, the scaffolds were exposed to a mixture of the template protein and a competitor protein with similar size but different chemistry. Lysozyme-imprinted polymers rebound 8.13 0.99% of lysozyme without any competition and 5.1 0.3% of the protein during competition. Lysozyme C peptide was imprinted into polysiloxane scaffolds to investigate the epitope approach to molecular imprinting. Without competition, 8.95 11.53% of the lysozyme preferentially bound to the scaffolds, while under competition 1.85 9.47% bound to the scaffolds. Lastly, bone morphogenetic protein 2 (BMP-2) was imprinted into the polymer scaffolds. Results revealed that BMP-2 imprinted scaffolds bound 10.09 6.625% under noncompetitive conditions and a very small 0.65 4.55% during competition. Trends of preferential binding via peptide imprinting and BMP-2 imprinting can be seen, and show promise in future tissue engineering material applications and biomaterial compatibility.

In this thesis, the lithium tantalite [LiTaO3, abbreviated to LT] thin films were deposited on Pt/Ti/SiO2/Si substrates by spin coating with sol-gel processing and rapid thermal processing. 1,3 propanediol was used as solvent to minimize the number of cycles of spin coating and drying processes to obtain the desired thickness of thin film. By changing the heating rate (600~3000¢J/min) and the heating temperature (500~800¢J), the effects of various processing parameters on the thin films growth are studied. In addition, the thermal isolation of detecting elements was achieved by the anisotropic wet etching of back silicon substrate. In order to reduce the thermal mass and thermal time constant of detector, the sensing element was built-up on a thin membrane. By changing the membrane thickness (20~350 £gm), the effects of various membrane thickness on the response of pyroelectric IR detector devices are studied also. Experimental results reveal that the heating rate will influence strongly on grain size, dielectricity, ferroelectricity and pyroelectricity of LT thin films. With the increase of heating rate, the grain size of LT thin film decreases slightly, and the c-axis orientation is enhanced. The relative dielectric constant (£`r ) of LT thin film increases from 28 up to 45.6, the dielectric loss (tan

Mesoporous WO3 powders were prepared via sol-gel processing synthesis using nonionic surfactant Pluronic (P-123) as the template. The influences of heating temperature on the pore structure and properties of WO3 powders were investigated. Three kinds of modifications were compared and evaluated after finding out the best heating condition. Different amount of lanthanum was doped into mesoporous WO3 to improve its Oxygen Reduction Reaction (ORR) activity. Several factors contributing to the increase of catalytic performance were discussed. Vulcan carbon powder was also used as a support to increase the catalysts’ electrical conductivity as well as dispersity. The component, microstructure and specific surface area of samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and N2 adsorption-desorption analysis. A three-electrode system with a rotating disk electrode (RDE) was used to detect samples’ electrochemical performance towards ORR in alkaline solutions. The as-prepared mesoporous La/WO3 powder with a ratio of La: W = 1: 10, calcined at 550℃ and supported by 25 wt% Vulcan carbon powder, exhibited highest ORR catalytic activity.

The goal of this research was the fabrication of thin films with magneto-optic (MO) properties. Accomplishment of this task was achieved via sol-gel processing of rare-earth and aluminum substituted yttrium-iron garnet (RxY3-xAlyFe5-yO12, R,Al:YIG), where R= Bi, Gd, Er, Ho. Detailed are the processing conditions, parameters and results leading to R,Al:YIG films with MO response. Success was attained with a 0.25M Gd,Al:YIG solution spin coated for 120 seconds at 3500rpm onto a (111) gadolinium gallium garnet (GGG) substrate and calcinated at 900°C for 4 hours. Samples were characterized via x-ray diffraction (XRD), magneto-optical loop tracer, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), profilometry and optical microscopy. / Master of Science

Polyorganosilany spadají do skupiny hybridních materiálů třídy II, které nabízejí nové možnosti materiálových funkcí a jejich vlastností. Ačkoliv byly v této kategorii již některé materiály zkoumány a stejně tak i jejich aplikace, nebyly doposud vlákna na základě polyorganosilanu v mikro a nano rozměru popsány což bylo motivací pro tuto práci. Předkládaná diplomová práce se zabývá podrobným zkoumáním poly(vinylmethyldimethoxysilanu) jako možného prekurzoru pro elektrostatické zvlákňování. Za účelem přípravy polymeru na bázi vinylmethylsilanu byla provedena radikálová polymerace a podmínky reakce byly modifikovány se záměrem změny molekulové hmotnosti získaného polymeru. Stupeň polymerace byl upravován na základě změny koncentrace iniciátoru a byl stanovován dynamickým rozptylem světla v roztoku polymeru a spektroskopickou metodou nukleární magnetické rezonance. Elektrostatické zvlákňování je velkou měrou spojeno s vlastnostmi roztoku a důraz byl proto kladen právě na zjištění těchto vlastností. Na základě experimentů bylo zjištěno, že syntetizovaný polymer je na přípravu vláken vhodný. Nicméně byly získány i fragmenty vláken a to s využitím polymeru v roztoku methanolu. Předpokladem zvlákňování je dostatek propojení mezi polymerními řetězci. Tento přístup byl studován se zapojením sol-gel postupu a bylo zjištěno, že fáze sol-gel procesu je velmi významná s ohledem na tvorbu vláken. Dalším využitým postupem pro získání vláken bylo začlenění dalšího polymeru do směsi jako nosiče a tímto postupem byla získána vlákna s různým průměrem.

<p><strong>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR).</strong></p><p>Mehanizam nastanka mulita zavisi od načina doziranja polaznih oblika reaktanata kao &scaron;to su alumina i silika. Dobijanje mulita sol-gel postupkom je u velikoj meri pobolj&scaron;ano u odnosu na klasično procesiranje zbog mogućnosti homogenog me&scaron;anja AI₂O₃ i SiO₂ komponenti i kontrole dodataka. Sol-gel metod omogućuje pripremu vrlo homogenih i reaktivnih gelova koji mogu da sinteruju na nižim temperaturama pri čemu se može postići vrlo fina mikrostruktura. U ovom radu koji se odnosio na procesiranje mulita sol-gel postupkom, hipoteza je bila da se na samom početku procesiranja aluminijumovi joni iz alkoholnog rastvora Al-soli uključuju u polimernu gel strukturu koju formira silika. Svrha ovog rada, je proučavanje uticaja procesnih promenjivih, dodatka fluornog jona i &ldquo;seedinga&rdquo; na temperaturu nastanka sol-gel mulita pri čemu se očekuje &scaron;to je moguće niža tempertura nastanka mulita (niža od 980⁰C). Polimerni sol je dobijen u prvom slučaju me&scaron;anjem TEOS-a i aluminijum nitrata nanohidrata koji je prethodno rastvoren u etil alkoholu. U drugom slučaju, u polimerni sol je dodavan fluorni jon u koncentraciji 2 do 5 % mas. u odnosu na očekivani prinos mulita i u trećem slučaju je dodavana različita količina mulitnih klica (2-4 % mas.). Eksperimantalno je potvrđeno da procesne promenljive; pH, temperatura geliranja i R odnos imaju, veliki uticaj na brzinu geliranja i na nastanak mulita. U slučaju dodavanja fluornog jona, potvrdena je hipoteza da fluorni jona na različite načine utiče na mehanizam nastanka mulita, pri čemu u prvom slučaju prisustvo fluornog jona obezbeduje mesta u oblastima razdvajanja granica faza nakon geliranja koja utiču na proces nukleacije. Ova mesta slično procesu kristalizacije stakla, omogućuju lak&scaron;u nukleaciju mulita prilikom njegove transformacije iz gela. Mesta na granici razdvanja faza postaju mesta na kojima se uspostavlja proces heterogene nukleacije &scaron;to je jedan od mogućih načina za snižavanje temperature nastanka mulita. Pored ovoga, dodavanje fluornog jona je doprinelo promeni mulitnih gel struktura, pri čemu je promena brzine hidrolize silike imala za posledicu promenu sadržaja vezane vode u toku geliranja &scaron;to se takođe značajno odražavalo na temperaturu nastanka mulita. Eksperimentalni rezultati termički obradenih gelova su pokazali, da dodavanje lluornog jona u polimerni mulitni sol stvara uslove za snižavanje temperature obrazovanja mulita sve do 890⁰C. U ovom radu je takođe pokazano da mulitne čestice, kao nukleanti pri &ldquo;seeding&quot; procesiranju, doprinose nastanku mulitnog gela koji nakon termičke obrade na 1000⁰C pokazuje veoma finu mikrostrukturu.</p> / <p><strong>Abstract was processed by technology for Optical character recognition (OCR).</strong></p><p>The mechanism of mullite formation depends upon the method of combining the alumina and silica containing reactants. Mullite can be obtained through the sol-gel process and can be greatly improved by the control of some reaction conditions particulaiiy by homogeneous mixing of Al2O3 and SiO2, and controlling of the additions. Sol-gel method allow preparation of very homogenous and reactive gels which can be sintering at low temperature and consequently submicronic microstructure can be reached. In this study of the mullite formation by sol-gel method, the hypothesis was that aluminium ions from alcoholic solulion of its salts incorporate to polymeric silica gel structure. The aim of this work was the investigation of the effect processing variables, fluorine addition and &ldquo;seeding&rdquo;on the temperature of sol-gel mullite formation and to obtain as lower temperature of mullite formation as possible (smaller than 980&deg;C). Polymeric sols, were prepared by the mixing of TEOS and aluminum nitrate nanohydrate dissolved in absolute ethyl alcohol and by adding fluorine ions in the second case from 2 wt.% to 5 wt.% and by different content of mullite seeded (2- 4 wt. %). Experimentally is determined that the processing variables as pH, gelling temperature and R ratio have high influence on the gelling rate and mullite formation. The hypothesis in the case of fluorine addition was that addition of fluorine ions could have different effects on the mechanism of mullite formation; the first it makes the sites at boundary of phase separation regions after gelling which influence at the process of the nucleation. These sites will act as a place for easy mullite nucleation, similar to process of the glass crystallization. The boundaries of the phase separation are the sites for heterogeneous nucleation which is one of the condition for lowering the temperature of mullite formation. Besides, fluorine addition could change the mullite gel structure (by changing the rate of hydrolyses of silica and it could change the content of bonded water during gelling), which should be very important for the temperature of mullite formation, too. The experimental results of heat treated gels showed that the addition of fluorine ion does decrease the temperature of mullite formation (in respect to classical sol-gel mullite processing) up to 8900C. As a nucleant in this study the mullite powder by &ldquo;seeding&rdquo; process contribute to muillite gel formation that after heat treatment up to 10000C showed very fine microstructure.</p>

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