• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.909-912
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• 2000

We synthesized polypyrrole (PPy) nanotubules by oxidative polymerization of the pyrrole monomer within the pores of a polycarbonate template. The electrochemical behavior was investigated using cyclic voltammetry. The redox potential was about -0.5 V vs. Ag/AgCl reference electrode, while the potential was about 0 V for PPy film. It is considered as the backbone grows according to the pore wall. Therefore, it is possible to be arranged regularly. That leads to improvement in the electron hopping. By electrochemical doping of glucose oxidase (GOx) on PPy nanotubules, an enzyme electrode has been fabricated. The kinetic parameter of biochemical reaction with glucose was evaluated. The formal Michaelis constant and maximum current calculated by computer were about 11.4 mmol $dm^3$ and 170.85 A respectively. Obviously, an affinity for the substrate and current response of the PPy nanotubules enzyme electrode are rather good, comparing with that of PPy film.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.234-238
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• 2007

Highly conducting Polypyrroles soluble in organic solvents were synthesized using functional doping agents, such as mixed dopants [sodium di(2-ethylhexyl)sulfosuccinate (DEHSNa) Naphthalenesulfonic acid (NSA), DEHSNa Toluenesulfonic acid (TSA), DEHSNa Dodecylbenzensulfonic acid (DBSA)] and mixed oxidants [$(NH_4)_2S_2O_8{\cdot}FeCl_3$, $(NH_4)_2S_2O_8{\cdot}Fe_2(SO_4)_3$]. Ppy-DEHS powder using an oxidant, such as $(NH_4)_2S_2O_8$ (10 wt%/vol.) showed higher solubility than the mixed dopant (DEHSNa NSA, 3 wt%/vol.) and mixed oxidant [$(NH_4)_2S_2O_8{\cdot}Fe_2(SO_4)_3$, 4 wt%/vol.] in DMF solvent. But Ppy-DEHS free standing film using a mixed dopant, such as DEHSNa NSA (16 S/cm) and a mixed oxidant, such as $(NH_4)_2S_2O_8{\cdot}Fe_2(SO_4)_3$ (13 S/cm) cast from DMF solvent showed higher electrical conductivity than $(NH_4)_2S_2O_8$ (2 S/cm). For the Ppy-DEHS films using various condition cast from DMF solvent, three dimensional various range hopping model (3D VRH ; $\{{\sigma}_{dc}(T)={\sigma}_oexp[-(T_o/T)^{1/4}]\}$) provided fit to the results of temperature dependence of electrical conductivity measurement.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.407-411
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• 1999

Studies have been carried out on the fabrication of PPy/GC and PPy/Pt electrode modified with polypyrrole film and determination of Cr(VI) by using 3-electrode system with modified electrodes. Modified electrodes were able to easily fabricated by cyclic voltammetry scanned from +1.0V to -1.0V(vs. Ag/AgCl) at 50 mV/sec. Film thickness could be controlled at same condition by the number of cycling up to 26 times. Reduction behaviour of Cr(VI) at PPy/GC electrode could be seen at wide potential ranges from +0.6V to -0.5V(vs. Ag/AgCl), and maximum reduction peak potential of the ion was observed at -0.25V(vs.Ag/AgCl). Calibration graph at its potential was linear from 0.1 ppm to 80.O ppm. Slope factor and relative coefficient were 1.75 mA/ppm and 0.998, respectively. Reduction behaviour of Cr(VI) at PPy/Pt electrode was similar to PPy/GC electrode, Calibration graph was linear from l.0 ppm to 60.0 ppm. Slope factor and relative coefficient were 0.5mA/ppm and 0.923, respectively. But PPy/GC modified electrode had about 3 times higher sensitivity than PPy/Pt modified electrode. Reduction behaviour of Cu(II), As(IlI), Pb(II), and Cd(II) couldn't be seen at PPy/GC electrode,Its metals had not lnterfered with Cr (VI) determination.

• Journal of the Korean Electrochemical Society
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• v.7 no.2
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• pp.100-107
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• 2004

The nano or micro sized structures of conducting polymer had been prepared by synthesizing the desired polymer within the pores of template of nano or micro porous membrane filter. In this study, we had tried to fabricate conducting polymer microstructures on an electrode by using electrochemical deposition adopting template synthesis. Our attention was focused on two different things, attaching template on the electrode and fabricating microstructures only at limited areas of the electrode. A conducting polymer, PEDiTT (poly 3,4-ethylenedithi-athiophene) solution was blended with PVA(polyvinyl alcohol) solution and used as an conducting adhesive. After attaching template membrane, the electrode were immersed in 0.5M pyrrole in 0.1M KCI solution, and electrochemical polymerization was performed. The growth process of the microstructures studied by SEM. The electrochemical fabrication of conducting polymer was performed by using two-electrode system. A large working electrode and a micro scale disc electrode were used for the confined area synthesis. Polymerization potential was 4V in an electrolytic solution made of KCI in deionized water. The optimum polymerization conditions were, i.e. (4V/100sec) for $250{\mu}m$ electrode and (6V/30 sec) for $10{\mu}m$ electrode.

• Journal of Sensor Science and Technology
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• v.23 no.6
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• pp.383-387
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• 2014

Electrically conductive polypyrrole-polyvinylpyrrolidone (PPy-PVP) nanofiber mats with a core-shell structure have been successfully fabricated by a two-step process: the formation of FeCl3-containing PVP nanofiber mat by electrospinning, and the vapor-phase polymerization (VPP) of pyrrole monomer on the mat in a sealed chamber at room temperature. Surface morphology and chemical composition of the PPy-PVP mat were characterized by SEM, EDX and FTIR analyses. The as-prepared nonwoven mat was composed of PPy-PVP nanofibers with an average diameter of 300 nm. The sheet conductivity of the nanofiber mat was measured to be approximately 0.01 S/cm by a four-point probe. We have also investigated gas-sensing properties of PPy-PVP nanofiber mat upon exposure to methanol vapor. The PPy-PVP nanofiber sensors were observed to have excellent methanol-sensing performance. The nanofiber-based core-shell nanostructure could give an opportunity to fabricate a highly sensitive and fast response sensor due to its high surfaceto-volume ratio.

• Journal of Sensor Science and Technology
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• v.15 no.3
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• pp.211-215
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• 2006

Conducting polymer (Polypyrrole) and Tin oxide ($SnO_{2}$) composite films have been fabricated with layer-by-layer technique. $SnO_{2}$ layer was screen-printed on $Al_{2}O_{3}$ substrate and then was dip-coated with polypyrrole (Ppy). The microstructures of composite films were evaluated by a field emission scanning electron microscope (FE-SEM) and FTIR spectral analysis. The change in sensitivity to various VOCs was observed. The target VOCs were methanol, ethanol, benzene and toluene. The sensitivities of the $Ppy/SnO_{2}$ sensor to benzene and toluene were very low at 1000 ppm (2.1 %, 1.5 %), while the sensitivities to methanol and ethanol was high (9 %, 11 %). It indicates that the sensors have selectivity to alcoholic gases such as methanol and ethanol.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.100-103
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• 2000

In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidase (GOx) forms a coordinate bond with the polymers backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized the enzyme electrode by electropolymerization added some organic solvent. A formative seeds of film growth is delayed by adding ethanol. The delay is induced by radical transfer between ethanol and pyrrole monomer. The radical transfer shares the contribution of dopant between electrolyte anion and GOx polyanion. This may lead to increase amount of immobilized the enzyme in PPy. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased. We established qualitatively that amount of immobilization can be improved by adding a little ethanol in the synthetic solution. It is due to radical transfer reaction. The radical transfer shares the contribution of dopant between small and fast electrolyte anion and big and slow GOx polyanion.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.421-424
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• 2006

Nafion/Pt/Polypyrrole composite membranes were fabricated by chemical in-situ polymerization of pyrrole monomers with Pt precursors in Nafion matrix for DMFC. We demonstrated that positively charged pyrrolinum groups of polypyrrole particles were co-interacted with sulfonic groups of Nafion as verified by FT-IR results. Mutual interaction between $Nafion-SO_3^-$ (or negatively charged Pt precursors) and Polypyrrole$-NH_2^+$ influenced the physical properties of pristine Nafion. Thermal property proton conductivity, methanol permeability, and cell performance of pristine and modified Nafion were analyzed for an application of DMFC membrane. Thermal stabilities of sulfonic groups and side chains in Nafion/Pt/polypyrrole composite membranes were higher than those of Nafion due to mutual interaction between sulfonic groups of Nafion and pyrrolinum groups of polypyrrole. Methanol permeabilities of Nafion/Pt/Polypyrrole composite were reduced more proton conductivities with the increase in the content of Pt particles. As a result of that, the enhancement of cell performance by Nafion/Pt/Polypyrole O2 relative to Nafion was more pronounced under the specific experimental condition such as high temperature and more concentrated methanol solution.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.6
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• pp.520-525
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• 2000

Glucose oxidase was immobilized in polypyrrole by electrosynthesis. The enzyme had an influence on the redox properties of a complex enzyme electrode. In the cyclic voltammograms of the enazyme electrode new peaks were appeared at the potential around 0.7V vs. Ag/AgCl in additional to the typical peaks for polypyrrole. The more immobilized the stronger the peaks became. During the cycling the pH of electrolyte solution was decreased to about 4.4 The reason for that is to be the proton released from the carboxyl in the glucose oxidase in order to keep on a charge neutrality of the oxidized enzyme. This fact suggests that the new peaks in the voltammograms are caused by the redox of glucose oxidase. In the AC impedance spectrum analysis of the electrode the diffusion of electrolyte anion was limited because of chained structure of the enzyme. The faradic impedance was large since the glucose oxidase is an insulator. Therefore when glucose oxidase is entrapped the enzyme should be limited in amount. Because the growth of the polypyrrole is accompanied both charge transfer and mass transport. For the traditional electrosynthesis that means amount of enzyme present in the electrode is limited to as much as film growable.

• Journal of the Korean Electrochemical Society
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• v.4 no.3
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• pp.94-97
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• 2001

Electro-conducting Polypyrrole(PPy) films were Prepared by applying constant current in various electrolytes solutions and their capacitance properties were investigated using cyclic voltammetry. Capacitance values were strongly dependent on the electrolytes solution used in electrochemical polymerization. PPy prepared in PC/AN mixture solution containing 0.5M $LiClO_4$ with small amount water showed 401 F/g and that electrogenerated in $AN/H_2O$ mixture solution containing 0.5M $LiClO_4$ retained $70\%$ of initial capacitance after 2000 cycles.