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Electro-optical sensor for the detection of extracellular ions
Bellan, Boris ; Salyk, Ota (referee) ; Vala, Martin (advisor)
The aim of this work was to prepare a platform based on electrochemical transistor that would allow both electrical and optical detection of ion exchange between the electrolyte and the layer of organic semiconductor. Semiconductor that have been used in this work was poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). The main goal was to verify whether the proposed platform meets the requirements of both characterization methods, and whether the sensitivity in the given arrangement is sufficient for the required range of analyte concentrations. The work also dealt with the study of the stability of the prepared platform in selected solvents and culture media, at the same time the method of optimizing the preparation of the photoresist foil and the completion of the OECT measuring cell was studied. A suitable solvent for polymethyl methacrylate was sought so that it did not affect the surrounding parts of the platform. Based on the obtained results, it was found that the selected photoresist for the preparation of the spacer frame is not suitable. However, it was found that the proposed platform satisfies both characterization methods. Therefore, it will be necessary to replace the current photoresist with a new, more chemically stable one.
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Nanostructured conducting polymer composites
Minisy, Islam ; Bober, Patrycja Magdalena (advisor) ; Kovalčík, Adriána (referee) ; Lisak, Grzegorz (referee)
Conducting polymers (CPs) combine the electrical properties of semiconductors and material properties of organic polymers. Polypyrrole (PPy) and polyaniline (PANI) are the most studied CPs due to their relatively high electrical conductivity (typically several units S cm-1 ), environmental stability, ease of preparation, good processability and low cost. Organic dyes have similar properties as surfactants, with an interesting ability to form various organized templates in water that could during synthesis tailor PPy morphologies to various nanostructures with high yield and improved electrical conductivity. Herein, PPy was prepared in the presence of cations dyes, safranin and phenosafranin, and anionic dye, methyl red, to obtain various nanostructures. The effect of dye concentration, oxidant-to-pyrrole mole ratio and other polymerization conditions on the physicochemical properties of the produced PPy was carefully investigated. Pyrrole was polymerized in the frozen reaction media at −24 řC in the presence of safranin, Acid Blue 25 (AB) or methyl orange (MO). Prepared one-dimensional nanostructures exhibited high yield and improved conductivity; the highest conductivity of 175 S cm−1 was obtained when safranin was used. Polypyrrole nanotubes prepared in the presence of MO were carbonized at 650...
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Organic-inorganic polymers - synthesis and characterization of hybrid polymers and nanocomposites
Depa, Katarzyna ; Strachota, Adam (advisor) ; Matějka, Libor (referee) ; Sedláček, Jan (referee)
In the first part of this work, silica nanoparticles and alternative or additional filler phases were incorporated into hydrogels based on the temperature-sensitive poly(N- isopropylacrylamide) (PNIPAm). Nano-SiO2-filled porous PNIPAm hydrogels with an enhanced force response (up to 100 g) to temperature stimuli were obtained by increasing several times the pore wall thickness, which was achieved via reducing the solvent (porogen) content during the gels' cryo-synthesis. A similar optimization of the force response was also carried out for analogous gels reinforced by nano-TiO2, in which the reinforcing effect of the filler is weaker. Partial intercalation of amylopectin starch into divinyl-crosslinked bulk as well as porous PNIPAm gels several times improved their extensibility. In case of starch-rich bulk gels, a very fast and extensive one-way deswelling in response to increased temperature was achieved (re-swelling upon cooling is much slower), which is attributed to specific properties of the starch-PNIPAm interface. In doubly-filled bulk PNIPAm/nano-SiO2/starch gels, a very strong synergic reinforcing effect of both fillers is observed, due to specific hydrogen bridging between the three phases. Highly porous cryogels based on PNIPAm/nano- SiO2/starch displayed a highly improved extensibility...
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Electro-optical sensor for the detection of extracellular ions
Bellan, Boris ; Salyk, Ota (referee) ; Vala, Martin (advisor)
The aim of this work was to prepare a platform based on electrochemical transistor that would allow both electrical and optical detection of ion exchange between the electrolyte and the layer of organic semiconductor. Semiconductor that have been used in this work was poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). The main goal was to verify whether the proposed platform meets the requirements of both characterization methods, and whether the sensitivity in the given arrangement is sufficient for the required range of analyte concentrations. The work also dealt with the study of the stability of the prepared platform in selected solvents and culture media, at the same time the method of optimizing the preparation of the photoresist foil and the completion of the OECT measuring cell was studied. A suitable solvent for polymethyl methacrylate was sought so that it did not affect the surrounding parts of the platform. Based on the obtained results, it was found that the selected photoresist for the preparation of the spacer frame is not suitable. However, it was found that the proposed platform satisfies both characterization methods. Therefore, it will be necessary to replace the current photoresist with a new, more chemically stable one.
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Book of Abstracts and Programme. Polymers and Organic Materials for Electronics and Photonics: Science for Applications. Prague Meeting on Macromolecules /81./
Pfleger, Jiří ; Cimrová, Věra
The book of abstracts contains the summary of 8 plenary and 24 invited lectures, accompanied by 38 oral contributions and 88 posters presented at the conference. The main areas covered were the design, synthesis, processing and characterization of novel functional organic materials and polymers, electrical, photoelectrical, optical and nonlinear optical phenomena, organic and hybrid electronic and photonic devices, and advanced materials and composites for biosensors, bioelectronics, and biophotonics. Particular session was dedicated to applications in flexible and wearable organic electronics and smart packaging. Due to big expectations in the application field of large area printed electronics, wearable devices, printed RFIDs, displays, solar cells and sensors there is a growing demand to prepare polymers with better defined morphology and chemical and structural stability. Hence, improvement in the molecular design and new synthetic and processing routes is strongly required. A special emphasis was given to attract the scientists from the application field of printed electronics to provide a necessary feedback for further development of new materials with desired properties.
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Organic-inorganic polymers - synthesis and characterization of hybrid polymers and nanocomposites
Depa, Katarzyna ; Strachota, Adam (advisor) ; Matějka, Libor (referee) ; Sedláček, Jan (referee)
In the first part of this work, silica nanoparticles and alternative or additional filler phases were incorporated into hydrogels based on the temperature-sensitive poly(N- isopropylacrylamide) (PNIPAm). Nano-SiO2-filled porous PNIPAm hydrogels with an enhanced force response (up to 100 g) to temperature stimuli were obtained by increasing several times the pore wall thickness, which was achieved via reducing the solvent (porogen) content during the gels' cryo-synthesis. A similar optimization of the force response was also carried out for analogous gels reinforced by nano-TiO2, in which the reinforcing effect of the filler is weaker. Partial intercalation of amylopectin starch into divinyl-crosslinked bulk as well as porous PNIPAm gels several times improved their extensibility. In case of starch-rich bulk gels, a very fast and extensive one-way deswelling in response to increased temperature was achieved (re-swelling upon cooling is much slower), which is attributed to specific properties of the starch-PNIPAm interface. In doubly-filled bulk PNIPAm/nano-SiO2/starch gels, a very strong synergic reinforcing effect of both fillers is observed, due to specific hydrogen bridging between the three phases. Highly porous cryogels based on PNIPAm/nano- SiO2/starch displayed a highly improved extensibility...
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Study of electrical and dielectric properties of conducting polymers
Varga, Martin ; Prokeš, Jan (advisor) ; Petzelt, Jan (referee) ; Pfleger, Jiří (referee)
Title: Study of electrical and dielectric properties of conducting polymers Author: Mgr. Martin Varga Department: Department of Macromolecular Physics Supervisor: RNDr. Jan Prokeš, CSc., Department of Macromolecular Physics Abstract: Charge transport in polyaniline (PANI) and polypyrrole (PPy) was studied in respect to various oxidants, dopants, morphology, and other modifica- tions in their synthesis. The mechanism of transport was discussed in the frame- work of combination of several models characteristic for disordered solids due to inherent heterogeneous structure of conducting polymers. Effect of drying on conductivity was studied and the long-time limit was explained with the diffusion- based model for bulk materials. For PPy nanotubes stability in strong alkaline media and aging were studied by AC and DC techniques. While conductivity of naturally aged samples after two years remained in the same order of magni- tude, after exposure to alkaline media or accelerated aging at high temperatures, conductivity decreased several orders of magnitude. Degraded material exhibited strong disorder and the transport model was completely changed. Despite severe treatment electrical properties were still comparable to other as-prepared mate- rials. Finally, an application example as ammonia sensor, the response of...
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Studium stejnosměrných a střídavých charakteristik polyanilinu v závislosti na technologii přípravy
Varga, Martin ; Prokeš, Jan (advisor) ; Valentová, Helena (referee)
Our aim in the present work is to provide and evaluate AC and DC characteristics of the polyaniline based materials. Different experiemtal techniques and devices have been used to achieve this goal. An introduction to the theoretical concepts of conductivity is given as well. The core of this thesis is an investigation of temperature and low pressure dependences, as well as the ageing effects for two systems (composites) in respect of the different preparation conditions such as dopants and their molar concentration, origin and the content of inorganic component and the way of polymerisation. An agreement with theoretical models is discussed.
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Conducting Polymers. Formation, Structure, Properties, and Applications
Stejskal, Jaroslav ; Trchová, Miroslava
Conducting polymers are studied because of their conductivity, as functional materials, and for their ability to respond to external stimuli. Polyaniline and polypyrrole are typical but by no means the only conducting polymers. They are investigated alone, or as components of compound materials. The synthesis of conducting polymers and the preparation of their composites, their structural characterization, their physical and chemical properties, and their applications both in well-established and new surprising directions are of interest. The conference booklet includes the abstracts of 7 invited plenary lectures, 45 contributed short lectures and 79 posters devoted to the chemistry, physics, and applied science of conducting polymers.
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