TY - GEN A1 - Lyutov, Vladimir V. A1 - Ivanov, Svetlozar D. A1 - Mirsky, Vladimir M. A1 - Tsakova, Vessela T. T1 - Polyaniline doped with poly(acrylamidomethylpropanesulphonic acid): electrochemical behaviour and conductive properties in neutral solutions T2 - Chemical Papers N2 - Poly(2-acrylamido-2-methyl-1-propanesulphonic acid) (PAMPSA)-doped polyaniline (PANI) layers are synthesised in the presence of sulphuric and perchloric acids. The effects of the inorganic acid as well as of the electrochemical synthetic procedure (potentiostatic and potentiodynamic deposition) and thickness of the polymer layers are studied. The focus is directed towards the pH dependence of the electrochemical redox activity and conductivity of the PAMPSA-doped PANI layers obtained under different conditions. Ascorbic acid oxidation is used as a test reaction to study the electrocatalytic behaviour of various PAMPSA-doped PANI layers in neutral solution. It is found that the type of inorganic component present in the polymerisation solution has a marked effect on the extent of doping in acidic solutions as well as on the redox electroactivity in neutral solutions. A comparison between potentiostatically and potentiodynamically synthesised layers at pH 7 shows a markedly lower conductance and lower extent of redox charge preservation in the case of potentiodynamic synthesis. The PANI electrocatalytic activity for ascorbic acid oxidation is also dependent on the polymer electrodeposition procedure, with potentiostatically synthesised layers exhibiting better electrocatalytic performance. KW - polyaniline KW - polyacids KW - PAMPSA KW - conductance KW - electrochemical Y1 - 2013 U6 - https://doi.org/10.2478/s11696-013-0341-9 SN - 1336-9075 VL - 67 IS - 8 SP - 1002 EP - 1011 ER - TY - GEN A1 - Ivanov, Svetlozar D. A1 - Kurniawan, Fredy A1 - Tsakova, Vessela T. A1 - Mirsky, Vladimir M. T1 - Automated layer-by-layer deposition of polyelectrolytes in flow mode T2 - Macromolecular Materials and Engineering N2 - Multilayer structures of conducting polymers were fabricated by a simply automated approach in flow mode. Polyaniline and poly(styrene sulfonate) were used as a model system, allowing a fast electrochemical and spectroscopic determination of the amount of deposited material. The technology was applied for layer-by-layer deposition of up to 100 bilayers. The results demonstrate a well reproducible and almost constant amount of the adsorbed polymer at each deposition cycle. The method can be applied for deposition of other conducting or non-conducting polymers, biological macromolecules and composites of polyelectrolytes and nanoparticles. Y1 - 2009 U6 - https://doi.org/10.1002/mame.200800376 SN - 1439-2054 VL - 294 IS - 6-7 SP - 441 EP - 444 ER - TY - GEN A1 - Tsakova, Vessela T. A1 - Ivanov, Svetlozar D. A1 - Lange, Ulrich A1 - Stoyanova, Aneliya A1 - Lyutov, Vladimir V. A1 - Mirsky, Vladimir M. T1 - Electroanalytical applications of nanocomposites from conducting polymers and metallic nanoparticles prepared by layer-by-layer deposition T2 - Pure and Applied Chemistry N2 - Layer-by-layer (LbL) deposition is a convenient technique for the formation of ultra-thin nanocomposite layers containing metallic nanoparticles (NPs) and conducting polymers (CPs). The advantages of this approach for producing composite layers suitable for electroanalytical applications are discussed. Examples of electroanalytical applications of LbL-deposited composites are presented. Composite layers consisting of polyaniline (PANI) and Pd NPs are used for hydrazine oxidation. The PANI–Au NPs system is applied for dopamine (DA) and uric acid (UA) oxidation. KW - conducting polymers KW - dopamine KW - electrochemistry KW - hydrazine KW - layer-by-layer deposition KW - nanoparticles KW - polyaniline (PANI) KW - uric acid Y1 - 2010 U6 - https://doi.org/10.1351/PAC-CON-10-08-01 SN - 1365-3075 VL - 83 IS - 2 SP - 345 EP - 358 ER - TY - GEN A1 - Ivanov, Svetlozar D. A1 - Lange, Ulrich A1 - Tsakova, Vessela T. A1 - Mirsky, Vladimir M. T1 - Electrocatalytically active nanocomposite from palladium nanoparticles and polyaniline: Oxidation of hydrazine T2 - Sensors and Actuators B: Chemical N2 - The layer by layer (LbL) adsorption technique was used to deposit a new electrocatalytic material consisting of palladium nanoparticles (Pd NPs) and polyaniline (PANI). As far as PANI adsorption did not affect the reactivity of the Pd NPs attached in the former adsorption step, the LbL technique offered the way of increasing the reactive Pd surface within a three-dimensional nanocomposite structure. In situ conductance measurements have shown that depending on the concentration of the PANI solution, used for the LbL adsorption, composites with either PANI-like (dependent on potential and pH) or metal-like (non-dependent on potential and pH) conductive behaviour can be obtained. Metal-like Pd NPs–PANI nanocomposites were studied as electrocatalytic materials for hydrazine oxidation. A linear concentration dependence of the voltammetric peak currents was observed in the 40–800 μM hydrazine concentration range, the sensitivity increasing with the amount of adsorbed Pd NPs. Amperometric measurements showed linear response in the 10–300 μM range with sensitivity 0.5 μA/μmol cm−2 and a theoretical detection limit estimated to be 0.06 μM. KW - Conducting polymers KW - Pd-nanoparticles KW - LbL adsorption KW - Hydrazine Y1 - 2010 U6 - https://doi.org/10.1016/j.snb.2010.07.004 SN - 0925-4005 VL - 150 IS - 1 SP - 271 EP - 278 ER - TY - GEN A1 - Lange, Ulrich A1 - Ivanov, Svetlozar D. A1 - Lyutov, Vladimir V. A1 - Tsakova, Vessela T. A1 - Mirsky, Vladimir M. T1 - Voltammetric and conductometric behaviour of self assembled multilayer nanocomposites of polyaniline and gold nanoparticles T2 - Journal of Solid State Electrochemistry N2 - Multilayer nanocomposites from polyaniline (PANI) and gold nanoparticles (AuNPs) were formed by layer-by-layer deposition. The formation of PANI–AuNPs multilayer structures was monitored by UV-vis absorption spectroscopy and cyclic voltammetry. Each deposited bilayer of PANI–AuNPs led to a monotonous and almost linear increase in both optical absorbance and the first current peak of PANI oxidation. The prepared multilayer nanocomposites were characterized by in situ conductivity measurements at different pH and potential and by transmission electron microscopy. Finally, chemosensitive properties of the new material based on the intrinsic affinity of gold nanoparticles were studied. Changes in the film resistance on exposure to vapors of mercury and sulfur-containing compounds were observed. KW - Polyaniline KW - Gold nanoparticles KW - Layer-by-layer deposition KW - Chemoresistor KW - In situ conductivity measurements KW - Nanocomposite Y1 - 2010 U6 - https://doi.org/10.1007/s10008-009-0922-2 SN - 1432-8488 SN - 1433-0768 VL - 14 IS - 7 SP - 1261 EP - 1268 ER - TY - GEN A1 - Ivanov, Svetlozar D. A1 - Tsakova, Vessela T. A1 - Mirsky, Vladimir M. T1 - Conductometric transducing in electrocatalytical sensors: Detection of ascorbic acid T2 - Electrochemistry Communications N2 - Conductometric transducing is suggested for electrocatalytic chemical sensors based on conductive polymers. Lateral conductivity of the polymer layers was measured by two- and four-point techniques. The approach was applied for electroanalytical detection of ascorbic acid on the electrocatalytically active polyaniline and poly-ortho-methoxyaniline electrodes. Both polymers displayed a monotonous concentration dependence of their conductance in the analytically important sub-millimolar concentration range of ascorbic acid. The approach was tested in model solutions of ascorbic acid in buffer and applied for detection of ascorbic acid in orange juice. KW - Chemical sensor KW - Conductometric sensor KW - Ascorbic acid KW - Electrocatalytical sensor KW - Electroactive polymers KW - Polyaniline KW - Poly-ortho-methoxyaniline Y1 - 2006 U6 - https://doi.org/10.1016/j.elecom.2006.02.006 SN - 1388-2481 VL - 8 IS - 4 SP - 643 EP - 646 ER -