• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.1-6
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• 2022

As the demand for wearable devices increases, many studies have been studied on the development of flexible electrode materials recently. In particular, the development of high-performance flexible electrode materials is very important for wearable sensors for healthcare because it is necessary to continuously monitor and accurately detect body information such as body temperature, heart rate, blood glucose, and oxygen concentration in real time. In this study, we fabricated the nonenzymatic glucose sensor based on polyaniline/carbon nanotube fiber (PANI/CNT fiber) electrode. PANI layer was synthesized on the flexible CNT fiber electrode through electrochemical polymerization process in order to improve the performance of a flexible CNT fiber based electrode material. Surface morphology of the PANI/CNT fiber electrode was observed by scanning electron microscopy. And its electrochemical characteristics were investigated by chronoamperometry, cyclic voltammetry, electrochemical impedance spectroscopy. Compared to bare CNT fiber electrode, this PANI/CNT fiber electrode exhibited small electron transfer resistance, low peak separation potential and large surface area, resulting in enhanced sensing properties for glucose such as wide linear range (0.024~0.39 and 1.56~50 mM), high sensitivity (52.91 and 2.24 ㎂/mM·cm²), low detection limit (2 μM) and good selectivity. Therefore, it is expected that it will be possible to develop high performance CNT fiber based flexible electrode materials using various nanomaterials.

• Polymer(Korea)
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• v.34 no.6
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• pp.511-516
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• 2010

The electrochemical coating of poly(3-octylthiophene) on carbon materials was studied in order to investigate the application possibility of the modified carbon materials in the photoelectronic devices. Commercial carbon paper and carbon fiber were used as substrate electrodes for electrochemical coating. The coating behaviors were analysed with the variation of monomer and electrolyte concentration, applied potential, and cycling number in cyclovoltammetry. The coating rate of poly(3-octylthiophene) formed on the substrate were proportional to the monomer and electrolyte concentration, applied potential, and cycling number with each independent exponent. The structure and morphology of electrochemically polymerized poly(3-octylthiophene) was investigated with scanning electron microscopy and FTIR reflectance measurement.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.928-932
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• 2008

A glassy carbon electrode (GCE) modified with poly(p-aminobenzene sulfonic acid) [Poly(p-ABSA)] film is fabricated by voltammetric technique in phosphate buffer solution (pH 8.0) containing $5.0\;{\times}\;10^{-3}\;mol\;L^{-1}$p- ABSA. Electrochemical behaviors of tryptophan at the Poly(p-ABSA) film electrode are investigated with voltammetry. The results indicate that the electrochemical response of tryptophan is improved significantly in the presence of poly(p-ABSA) film. Compared with the bare glassy carbon electrode, the Poly(p-ABSA) film electrode remarkably enhances the irreversible oxidation peak current of tryptophan. Some parameters such as voltammetric sweeping segments for the electrochemical polymerization, pH, accumulation potential and accumulation time are optimized. Under the optimal conditions, the oxidation peak current is proportional to tryptophan concentration in the range of $1.0\;{\times}\;10^{-7}$ to $1.0\;{\times}\;10^{-6}\;mol\;L^{-1}$, and $2.0\;{\times}\;10^{-6}$ to $1.0\;{\times}\;10^{-5}\;mol\;L^{-1}$ with a detection limit of $7.0\;{\times}\;10^{-8}\;mol\;L^{-1}$. The proposed procedure is successfully applied to the determination of tryptophan in a commercial amino acid oral solution.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.210-215
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• 2022

Two types of lignin materials with a different surface ionic character were used and polypyrrole layer was introduced on the lignin surface to obtain polypyrrole@lignin and polypyrrole@lignosulfonate composites using a simple chemical oxidation polymerization, reported in a previous article. Polypyrrole was effectively prepared regardless of the lignin type and the resulting composites were investigated using scanning electron microscope (SEM), cyclic voltammetry (CV), and impedance analysis. SEM and CV results showed that the obtained composites retained stable electrochemical properties after introduction of polypyrrole on the lignin surface. Impedance analyses showed that the surface properties of composites were dependent on lignin characteristics. In addition, the composites were embedded in agarose, an gelifying agent, to obtain conductive gels. It was found that the conductive gels possessed an electrical conductivity and also retained stable electrochemical properties, which indicated that the conductive gels might be useful for some applications.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.233-237
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• 2024

This study is about the fabrication of a flexible electrode based on PAN-based carbon fibers tow using organic/inorganic nanocomposite and its application of non-enzymatic sensor. The organic/inorganic nanocomposite was composed of the conductive polymer polyaniline (PANI) and the metal oxide CuO. And glucose was used as the target of the electrochemical sensor. Commercialized CFTs were pretreated through heat treatment for desizing and electrochemical oxidation for activation. This nanocomposite was sequentially synthesized on the pretreated CFT surface using electrochemical polymerization and electrochemical deposition. Finally, the CFT/PANI/CuO NPs electrode was obtained. The electrochemical properties and sensing performance of the CFT/PANI/CuO NPs electrode were analyzed using chronoamperometry (CA), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The sensitivity of the CFT/PANI/CuO NPs electrode was about 8.352 mA/mM (in a linear range of 0.445~6.674 mM) and 3.369 mA/mM (in a linear range of 6.674~50 mM), respectively. So, the CFT/PANI/CuO NPs electrode exhibited the enhanced sensing performances due to unique properties such as small peak potential separation, low electron transfer resistance, and large specific surface area.

• Clean Technology
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• v.20 no.4
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• pp.415-424
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• 2014

In this study, two kinds of polymer (PPQX-2hdPTZ (P1), POPQX-2hdPTZ (P2)) were synthesised by Suzuki coupling reaction based on phenothiazine derivative as electron-donor and quinoxaline derivative as electron-acceptor. Microwave synthesis workstation was used to shorten the polymerization time and increase the degree of polymerization. The physical, thermal stability, optical and electrochemical properties of the synthesized polymer were confirmed. The thermal stability of two polymers was outstanding as the initial decomposition temperature was $323-328^{\circ}C$. And additional substituted alkoxy chain on P2 showed higher degree of polymerization. An analysis of electrochemical properties, all polymer had similar HOMO energy level values. Device was fabricated by ITO/PEDOT:PSS/active layer/$BaF_2$/Al structure and photovoltaic properties were confirmed. Each device has a different film thickness and the resulting change in PCE was confirmed. As a result the thinner thickness of the film showed a high efficiency ($PCE_{max}:P1=1.0%$, P2 = 1.1%).

• Journal of the Korean Electrochemical Society
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• v.14 no.2
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• pp.83-91
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• 2011

Mesoporous titanium dioxide ($TiO_2$) thin films were prepared using poly(vinyl chloride)-graft-poly(N-vinyl pyrrolidone) (PVC-g-PVP) as a templating agent via sol-gel process. Grafting of PVC chains from PVC backbone was done by atom transfer radical polymerization (ATRP) technique. The successful grafting of PVP to synthesize PVC-g-PVP was checked by fourier-transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The carbonyl group interaction of PVC-g-PVP graft copolymer with $TiO_2$ was confirmed by FT-IR. The porous morphologies of the $TiO_2$ films genereated after calcination at $450^{\circ}C$ was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mesoporous $TiO_2$ films with 580 nm in thickness were used as a photoelectrode for solid state dye sensitized solar cell (DSSC) and showed an energy conversion efficiency of 1.05% at 100 $mW/cm^2$.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.245-250
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• 2009

Crosslinked membrane based on sulfonated polyimide was prepared by the introduction of crosslinkable monomer in polymerization process and crosslinking during membrane casting. Crosslinked membranes showed different properties from non-crosslinked membranes. Crosslinking decreased methanol crossover and therefore unit cell using crosslinked membrane showed increased open circuit voltage, 0.81 V, in comparison with unit cell using noncrosslinked membrane, 0.71 V. In addition, water uptake of crosslinked membrane, 40.5%, was lower than that of non-crosslinked membrane, 57.0%, and this resulted in improved dimensional stability. However, proton conductivity of crosslinked membranes showed rather low relative to non-crosslinked membrane due to reduced water uptake.

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1609-1612
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• 2003

The electrooxidation of 8-(3-acetylimino-6-methyl 2,4-dioxopyran)-1-aminonaphthaline (AMDAN) in aqueous and non aqueous media led to the formation of polymeric films, poly (AMDAN). The monomer, undergo anodic oxidation through the formation of a monocation radical irrespective of the nature of the medium. In aqueous medium, the monocation radical undergoes, through its resonance structures, dimerisation involving tail-to-tail, head-to-tail and even head-to-head coupling. The products formed, being more easily oxidisable than the parent substance, undergo further oxidation at the same potential so that the overall oxidation involves a one-step (i.e., a single wave), two-electron process. In non-aqueous medium, the monocation radical does not undergo dimerisation through coupling reactions. Retaining its identity, monomer oxidise in two steps involving one electron in each step. The fact that the cathodic peaks corresponding to these anodic peaks are rarely observed indicates fast consumption of the electrogenerated monocation radicals and dications by follow-up chemical reactions to produce polymeric products (poly AMDAN). The electrochemical behavior of the formed polymer films was investigated in both non aqueous and aqueous media. The films prepared in non aqueous medium were found to be more electroactive than that the films prepared in aqueous medium. This is confirmed with the results in litreature which illustrate that the film prepared in aqueous solution hold water in its structure via hydrogen bonding, which causes decomposition reactions.

• Journal of the Korean institute of surface engineering
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• v.36 no.1
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• pp.9-13
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• 2003

Plasma polymerized organic thin films were deposited on Si(100), glass and metal substrates at $25∼100 ^{\circ}C$ using thiophene and toluene precursors by PECVD method. In order to compare physical and electrochemical properties of the as-grown thin films, the effects of the RF plasma power in the range of 30∼100 W and deposition temperature on both corrosion protection efficiency and physical properties were studied. We found that the corrosion protection efficiency ($P_{k}$), which is one of the important factors for corrosion protection in the interlayer dielectrics of microelectronic devices application, was increased with increasing RF power. The highest $P_{k}$ value of plasma polymerized toluene film (85.27% at 70 W) was higher than that of the plasma polymerized thiophene film (65.17% at 100 W), indicating inhibition of oxygen reduction. The densely packed and tightly interconnected toluene film could act as an efficient barrier layer to the diffusion of molecular oxygen. The result of contact angle measurement showed that the plasma polymerized toluene films have more hydrophobic surface than those of the plasma polymerized thiophene films.