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Atomic force microscopy of soft materials
Šudáková, Anna ; Havlíková, Martina (referee) ; Smilek, Jiří (advisor)
This bachelor thesis focuses on atomic force microscopy (AFM), mainly on studying the measurement procedure and optimalization of measurement conditions with future perspective on imaging hydrogels and measuring mechanical properties (such as adhesion or stiffness) of hydrogels and semi-rigid materials at the microlevel. Atomic force microscopy is gaining significant importance in research due to its versatility, when it can provide topographical image of conductive and non-conductive samples while measuring mechanical properties of the samples, such as adhesion, elasticity or stiffness. Advantage of AFM method is that it can provide mechanical properties of the samples not only on macro levels as we are used to, for example, from rheology, but also on local level. Optimalization was performed on standard sample, one micrometre polystyrene nanoparticles , when the individual modes were measured, such as non-contact (AC Mode Imaging) mode and quantitative mode (QITM Advanced Imaging). This was followed by the measurement of a PVA foils, the measurement was performed because they are xerogels and will be studied more in the future. They were made with polyvinyl alcohol and chitosan. The internal environment of the hydrogels has been modified by adjusting the pH (NaOH) or by changing the ionic strength (NaCl). Furthermore, the effect of freezing on the PVA foils was observed, it is one of the possible ways of preparation of physically linked hydrogels. This work also examines the effect of porosity on concentration of physically linked thermoreversible agarose gels.
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Preparation, characterization layered hydrogel electrospun materials and determination of transport characteristics
Šudáková, Anna ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
V dnešní době je stále velký problém efektivního dodávání léčiv do lidského těla. Stále se jedná o příjem léčiva s konstantní koncentrací, která se uvolní v krátkém čase, což není velice efektivní. Proto došlo k zaměření se na vývoj nového způsobu dodávání léčiv pomocí tzv. postupného uvolňování, které by zamezilo rychlému uvolnění velké koncentrace léčiva do těla. Tento problém je zde řešen pomocí kompozitního materiálu složeného z netkané textilie, která zde funguje jako nosič hydrogelu, který v tomto případě prozatím nese barvivo pro stadium kinetiky uvolňování. Netkaná textilie z polypropylenu je zde zkoumána ve spojení s hydrogely alginátu, chitosanu a želatiny. Materiály byly studovány na to, jestli, a jak moc docházelo k uvolňování samotného hydrogelu z vrstevnatého materiálu pomocí uvolňování do prostředí vody. Toto bylo měřeno pomocí metody viskozimetrie. Následně byla zjišťována kinetika uvolňování skrz materiály s různým počtem vrstev pomocí metody difúzních cel. Poslední část práce se zaměřuje na studium uvolňování barviva (methylenové modři) z vrstevnatého materiálu, který obsahuje právě gradient tohoto barviva.
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Atomic force microscopy of soft materials
Šudáková, Anna ; Havlíková, Martina (referee) ; Smilek, Jiří (advisor)
This bachelor thesis focuses on atomic force microscopy (AFM), mainly on studying the measurement procedure and optimalization of measurement conditions with future perspective on imaging hydrogels and measuring mechanical properties (such as adhesion or stiffness) of hydrogels and semi-rigid materials at the microlevel. Atomic force microscopy is gaining significant importance in research due to its versatility, when it can provide topographical image of conductive and non-conductive samples while measuring mechanical properties of the samples, such as adhesion, elasticity or stiffness. Advantage of AFM method is that it can provide mechanical properties of the samples not only on macro levels as we are used to, for example, from rheology, but also on local level. Optimalization was performed on standard sample, one micrometre polystyrene nanoparticles , when the individual modes were measured, such as non-contact (AC Mode Imaging) mode and quantitative mode (QITM Advanced Imaging). This was followed by the measurement of a PVA foils, the measurement was performed because they are xerogels and will be studied more in the future. They were made with polyvinyl alcohol and chitosan. The internal environment of the hydrogels has been modified by adjusting the pH (NaOH) or by changing the ionic strength (NaCl). Furthermore, the effect of freezing on the PVA foils was observed, it is one of the possible ways of preparation of physically linked hydrogels. This work also examines the effect of porosity on concentration of physically linked thermoreversible agarose gels.
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