Browsing by Author "Kuželová Košťáková, Eva"

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    Biofyzika I
    (2020-01-01) Lukáš, David; Trčka, Michal; Kuželová Košťáková, Eva; Jenčová, Věra; Asatiani, Nikifor
    Cílem projektu je vytvoření učebního textu (skript) k novému předmětu Biofyzika v rámci nově akreditovaného SP Bioinženýrství.
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    Crystallinity of Electrospun and centrifugal spun polycaprolactone fibers: A Comparative Study
    (HINDAWI LTD, ADAM HOUSE, 3RD FLR, 1 FITZROY SQ, LONDON, W1T 5HF, ENGLAND, 2017-01-01) Kuželová Košťáková, Eva; Blažková, Lenka; Lukáš, David; Mašková, Gabriela
    Crystalline properties of semicrystalline polymers are very important parameters that can influence the application area. The internal structure, like the mentioned crystalline properties, of polymers can be influenced by the production technology itself and by changing technology parameters. The present work is devoted to testing of electrospun and centrifugal spun fibrous and nanofibrous materials and compare them to foils and granules made from the same raw polymer. The test setup reveals the structural differences caused by the production technology. Effects of average molecular weight are also exhibited. The applied biodegradable and biocompatible polymer is polycaprolactone (PCL) as it is a widespread material for medical purposes. The crystallinity of PCL has significant effect on rate of degradation that is an important parameter for a biodegradable material and determines the applicability. The results of differential scanning calorimetry (DSC) showed that, at the degree of crystallinity, there is a minor difference between the electrospun and centrifugal spun fibrous materials. However, the significant influence of polymer molecular weight was exhibited. The morphology of the fibrous materials, represented by fiber diameter, also did not demonstrate any connection to final measured crystallinity degree of the tested materials.
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    Fabrication of dual-functional composite yarns with a nanofibrous envelope using high throughput AC needleless and collectorless electrospinning
    (NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND, 2019-02-12) Valtera, Jan; Kalous, Tomáš; Pokorný, Pavel; Baťka, Ondřej; Bílek, Martin; Chvojka, Jiří; Mikeš, Petr; Kuželová Košťáková, Eva; Žabka, Petr; Ornstová, Jana; Beran, Jaroslav; Stanishevsky, Andrei; Lukáš, David
    Nanotechnologies allow the production of yarns containing nanofibres for use in composites, membranes and biomedical materials. Composite yarns with a conventional thread core for mechanical strength and a nanofibrous envelope for functionality, e.g. biological, catalytic, have many advantages. Until now, the production of such yarns has been technologically difficult. Here, we show an approach to composite yarn production whereby a plume of nanofibers generated by high throughput AC needleless and collectorless electrospinning is wound around a classic thread. In the resulting yarn, nanofibres can form up to 80% of its weight. Our yarn production speed was 10 m/min; testing showed this can be increased to 60 m/min. After the yarn was embedded into knitwear, scanning electron microscope images revealed an intact nanofibrous envelope of the composite yarn. Our results indicate that this production method could lead to the widespread production and use of composite nanofibrous yarns on an industrial scale.
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    Nanovlákna. Teorie, technologie a použití
    (2020-01-01) Lukáš, David; Kuželová Košťáková, Eva; Jenčová, Věra