|
|
Study of Thiophene Oligo-copolymers: Synthesis and Optoelectronic Properties
Krajčovič, Jozef ; Mazal,, Ctibor (referee) ; Kapička, Vratislav (referee) ; Friedl, Zdeněk (advisor)
Thesis presents synthesis and study of thiophene monomers, oligomers and polymers. The new series of thieno[3,4-b]pyrazine copolymers based on 3-dodecylthiophene and pyrazine monomers were prepared by oxidative polymerization with FeCl3. The effective synthetic method for preparation of 3-alkylthiophenes and thiophene oligomers was developed by optimizing of Kumada cross-couplig. The mentioned method could be realized for multikilos scale with possibility of transfer to pilot plant production. The second part of thesis focuses on synthesis and study of new thiophene compounds, which consist of both 2,3-diazo-1,3-butadiene bridge with two terminal chromophores and two thiophene units linked together via -position by pyrazine or hydrazine bridge. Finally, the new type of regular alternating copolymer consists of 2,2´:5´,2´´-terthiophene-5,5´-dicarboxylic acid (TEDA) and polyethyleneoxide (PEO) was prepared. Formation of polymer nano-subunits as separated phases in solid state was confirmed by TEM.
|
|
|
Preparation of diketopyrrolopyrrole-based (DPP) polymers for organic electronics
Solanský, Lukáš ; Veselý, Dominik (referee) ; Cigánek, Martin (advisor)
The modern world is burdened by dependence on electricity and problems with its production. A very advantageous way to gain electricity is through photovoltaics. However, the production of silicon solar cells is demanding and expensive with a high impact on the environment. For this reason, there is an effort to switch to solar cells based on organic semiconductors. These include, for example, polymers based on diketopyrrolopyrrole (DPP). The theoretical part of this thesis deals with organic electronics, conductive polymers and DPP-based polymers, their properties and applications. It further describes the most common synthetic approaches to DPP-based polymers. The experimental part of this final work describes the preparation of intermediates necessary for the synthesis of the resulting DPP-based polymers using Stille reaction. The thiophene derivative of DPP was N,N'alkylated and subsequently brominated. Furthermore, organotin intermediates were prepared, which together with the dibrominated DPP derivative participate in the polymerization.
|
|
|
Organic semoconductors and devices
Kočer, Martin ; Doc.Ing.Ota Salyk, CSc. (referee) ; Špinka, Jiří (advisor)
Introduction part of this bachelor's thesis deals about general properties of organic semiconductors, their structure and features of selected representatives. The middle section deals with some methods of application of organic semiconductors and organic devices. The final section deals about practical production of polyaniline samples and their analysis.
|
|
|
Advanced materials for organic electronics and bioelectronics
Šudomová, Lucie ; Márová, Ivana (referee) ; Weiter, Martin (advisor)
This bachelor thesis focuses on the characterization of organic materials with semiconductor properties in terms of their potential use in bioelectornic applications. The theoretical part is summarizing the basic characteristics of organic materials for organic electronics and bioelectronic. There are mentioned basic structures and general properties of relevant substances. This part of the thesis also describes the basic principles of devices for bioelectronic applications and its use. Practical part includes preparation of thin films of two types substances: on the basis of low-molecular organic substances (6,13-bis(triisopropylsilylethynyl) pentacene and diketopyrrolopyrrole) and another based on polymers (Poly (3-hexylthiophene-2,5-diyl) and Poly (3,4-ethylenedioxythiophene): poly (styrene sulfonic acid) and). The first part of the experiment is focused on the characterization of the properties of used substances. The second part examines microbial biocompatibility
|
|
|
Preparation of diketopyrrolopyrrole-based (DPP) polymers for organic electronics
Solanský, Lukáš ; Veselý, Dominik (referee) ; Cigánek, Martin (advisor)
The modern world is burdened by dependence on electricity and problems with its production. A very advantageous way to gain electricity is through photovoltaics. However, the production of silicon solar cells is demanding and expensive with a high impact on the environment. For this reason, there is an effort to switch to solar cells based on organic semiconductors. These include, for example, polymers based on diketopyrrolopyrrole (DPP). The theoretical part of this thesis deals with organic electronics, conductive polymers and DPP-based polymers, their properties and applications. It further describes the most common synthetic approaches to DPP-based polymers. The experimental part of this final work describes the preparation of intermediates necessary for the synthesis of the resulting DPP-based polymers using Stille reaction. The thiophene derivative of DPP was N,N'alkylated and subsequently brominated. Furthermore, organotin intermediates were prepared, which together with the dibrominated DPP derivative participate in the polymerization.
|
|
|
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...
|
|
|
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...
|
|
|
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...
|
|
|
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...
|
|
|
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.
|
guest ::
