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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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Materials combining conducting polymers and noble metals
Bober, Patrycja Magdalena ; Stejskal, Jaroslav (advisor) ; Omastová, Mária (referee) ; Pron, Adam (referee)
Polyaniline-silver composites combine the electrical properties of metals and the material properties of polymers. Polyaniline is one of the most studied conducting polymers on account of high electrical conductivity (units S cm-1 ), environmental stability, ease of preparation from common chemicals, good processibility and low cost. Silver is well known because of its highest conductivity among metals (500 000 S cm−1 ), antibacterial properties, and low price compared to other noble metals. Aniline was oxidized with silver nitrate in acidic aqueous medium to polyaniline-silver composite. The presence of different organic acids was studied. The most promising became methanesulfonic acid solution, in which most problems (such as inhomogeneity of samples and limited solubility of silver salts) got solved. The oxidation of aniline with silver nitrate is slow and takes over several months to get a reasonable yield. An addition of a small amount of p-phenylenediamine, even 1 mol. % relative to aniline, shortens the reaction time to several hours or even to tens of minutes. Small amounts of ammonium peroxydisulfate had similar effect. The content of silver in composites is fixed by the stoichiometry of reaction, and composites always contain ≈70 wt.% of silver. By using mixed oxidants, silver nitrate and...
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Materials combining conducting polymers and noble metals
Bober, Patrycja Magdalena ; Stejskal, Jaroslav (advisor) ; Omastová, Mária (referee) ; Pron, Adam (referee)
Polyaniline-silver composites combine the electrical properties of metals and the material properties of polymers. Polyaniline is one of the most studied conducting polymers on account of high electrical conductivity (units S cm-1 ), environmental stability, ease of preparation from common chemicals, good processibility and low cost. Silver is well known because of its highest conductivity among metals (500 000 S cm−1 ), antibacterial properties, and low price compared to other noble metals. Aniline was oxidized with silver nitrate in acidic aqueous medium to polyaniline-silver composite. The presence of different organic acids was studied. The most promising became methanesulfonic acid solution, in which most problems (such as inhomogeneity of samples and limited solubility of silver salts) got solved. The oxidation of aniline with silver nitrate is slow and takes over several months to get a reasonable yield. An addition of a small amount of p-phenylenediamine, even 1 mol. % relative to aniline, shortens the reaction time to several hours or even to tens of minutes. Small amounts of ammonium peroxydisulfate had similar effect. The content of silver in composites is fixed by the stoichiometry of reaction, and composites always contain ≈70 wt.% of silver. By using mixed oxidants, silver nitrate and...
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