• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.28-29
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• 1995

분리막의 고유기능인 분리기능 뿐 아니라 에너지의 절약을 위하여 분리막공정의 활용은 화학산업 전반에 걸쳐 급격히 신장되고 있다. 따라서 분리막의 효율적인 이용을 위한 연구가 활발히 진행되고 있으며, 특히 분리막 공정의 활용범위를 제한하고 있는 단점(fouling)에 대한 연구를 중심으로 분리막의 소재개발 및 이미 개발되어 잇는 소재의 변형을 통하여 분리막의 응용 범위를 넓혀가고 있다. 본 실험에서는 새로운 소재를 개발하고, 개발된 소재를 토대로 변형공정 및 분리막제조 공정의 변화를 첨가하여 최종 분리막의 구조를 관찰하였다. 또한 분리막의 성능에 대한 변형 공정의 영향을 조사하였다. 분리막의 소재로써 PS(polystyrene)을 채택하였으며, DVB(divinylbenzene)을 이용하여 UV 중합으로 기공의 조절을 시도하였고, 변형공정으로 sulfonation을 하였다. 또한 고분자 열중합으로 PSS[poly(sodium4-styrnesulfate)] 분리막을 제조하였으며, 변형공정에 따른 분리막 구조의 변화를 관찰하고 규명하였다.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.99-103
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• 2013

An emzymatic bioanode for a glucose/oxygen biofuel cell was prepared by the sequential coating of carbon nanotube (CNT), charge transfer complex (CTC) based on tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF), glucose oxidase (GOx), and polyion complex (mixture of poly-L-lysine hydrobromide and poly (sodium 4-styrenesulfonate)) on a glassy carbon electrode. A biocathode was also prepared by the sequential coating of CNT, bilirubin oxidase (BOD), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and polyion complex. The effect of CNT and CTC on the electrochemical performance was investigated. The biofuel cell exhibited a promising performance with maximum power densities of 3.6, 10.1, and $46.5{\mu}W/cm^2$ at 5, 20, and 200 mM of glucose concentration, respectively. The result indicates that the biofuel cell architecture prepared in this study can be used in the development of biofuel cells and biosensors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.49-49
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• 2009

Nanocomposites of gold nanoparticles and multi-walled carbon nanotubes (MWNTs) were prepared by electrostatic interaction. Gold nanopartic1es were stabilized by polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and poly(sodium-4-styrenesulfonate) (PSS) in aqueous medium, and MWNTs were modified by poly(diallyldimethylammonium)chloride (PDDA) in water. The as-perpared Au-MWNT nanocomposites were structurally and electrically characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV/Vis spectroscopy, X-ray photoelectron spectroscopy (XPS) and cyclo voltammetry (CV). UV/Vis spectra of Au-MWNT nanocomposites showed the characteristic surface plasmon bands in the range of ~515nm, depending on the stabilizers. There is only slight change on the band shape with variation of stabilizing agents for gold nanoparticles. Through FE-SEM and TEM images, the distribution of gold, nanoparticles on the sidewalls of MWNTs was deliberately investigated on Au-MWNT nanocomposites treated with different stabilizers. XPS and CV showed redistribution of electron densities and changes in the binding energy states of nanopartic1es in nanocomposite respectively.

• Macromolecular Research
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• v.17 no.9
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• pp.658-665
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• 2009

This study examined the effects of the sodium salts of aliphatic dicarboxylic acids (DCAs) on the dynamic mechanical properties and morphology of two sets of poly(styrene-co-sodium methacrylate) (MNa) and poly(styrene-co-sodium styrenesulfonate) (SNa) ionomers. When the DCA content was relatively low, the ionic moduli of the MNa and SNa ionomers increased but the matrix and cluster glass transition temperature ($T_g$) did not change significantly. The increasing ionic modulus was almost independent of the type of the ionic groups of the ionomer, and the chain length of DCAs. When a large amount of the sodium succinate (DCA4) was added to the MNa and SNa ionomers, the ionic moduli of the two ionomers increased strongly but the matrix and cluster $T_g's$ increased slightly and significantly, respectively. In the case of sodium hexadecanedioate (DCA 16), DCA 16 increased the ionic moduli of the two ionomers. The addition of DCA16 changed the matrix and cluster $T_g's$ of the MNa ionomer slightly, but decreased the cluster $T_g$ of the SNa ionomer significantly with no change in the matrix $T_g$. In addition, the DCA-containing ionomers showed an X-ray diffraction peak indicating the presence of ordered domains of DC As in the ionomers. Hence, DCA4 acts mainly as a reinforcing filler in MNa and SNa systems. In the case of DCA 16, it initially behaved like a filler but also functioned as a preferential plasticizer for the clusters at high content.

• Korea-Australia Rheology Journal
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• v.15 no.1
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• pp.1-7
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• 2003

A new method is introduced to build up organic/organic multilayer films composed of cationic poly(allylamine hydrochloride) (PAH) and negatively charged poly (sodium 4-styrenesulfonate) (PSS) using the spinning process. The adsorption process is governed by both the viscous force induced by fast solvent elimination and the electrostatic interaction between oppositely charged species. On the other hand, the centrifugal and air shear forces applied by the spinning process significantly enhances desorption of weakly bound polyelectrolyte chains and also induce the planarization of the adsorbed polyelectrolyte layer. The film thickness per bilayer adsorbed by the conventional dipping process and the spinning process was found to be about 4 ${\AA}$ and 24 ${\AA}$, respectively. The surface of the multilayer films prepared with the spinning process is quite homogeneous and smooth. Also, a new approach to create multilayer ultrathin films with well-defined micropatterns in a short process time is Introduced. To achieve such micropatterns with high line resolution in organic multilayer films, microfluidic channels were combined with the convective self-assembly process employing both hydrogen bonding and electrostatic intermolecular interactions. The channels were initially filled with polymer solution by capillary pressure and the residual solution was then removed by the .spinning process.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.729-734
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• 2002

In this study, the polyaniline films of emeraldine base(EB) and lucoemeraldine base(LEB) form chemically doping with poly(sodium-4 styrenesulfonate, PSS) were prepared by casting the mixed solution of chloroform and m-cresol on ITO(indium tin oxide) electrode. By analyzing UV-vis spectra of the mixed solutions, the effects of the secondary doping by m-cresol were obtained. And the conductivity of polyaniline film was increased with increasing m-cresol content. The results suggest that the improvement of conductivity obtained by secondary doping results primarily from interaction of polyaniline and m-cresol. As the results of analyzing cyclic voltammograms, it was known that the redox peak currents of polyaniline electrode prepared from LEB were larger and more reversible than those of polyaniline electrodes prepared from EB. The charge transfer resistances($R_{ct}$) of polyaniline electrodes were reduced with increasing m-cresol content, and LEB/PSS electrodes were smaller than EB/PSS electrodes. This result agrees to the analysis of the redox peak current of cyclic voltammograms. The solution resistance and the capacity of electrical double layer almost unchanged in all prepared polyaniline electrodes. It was confirmed that solution resistance was independent of frequency factor in AC impedance spectra. Also the polyaniline film doping with PSS was revealed pseudo n-type characteristics of conducting polymer.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.258-263
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• 2023

In this study, conductive polymers and the enzyme tyrosinase (Tyr) were deposited on the surface of a screen printed carbon electrode (SPCE), which can be fabricated as a disposable sensor chip, and applied to the detection of bisphenol F (BPF), an endocrine disruptor with proven links to male diseases and thyroid disorders, using electrochemical methods. On the surface of the SPCE working electrode, which was negatively charged by oxygen plasma treatment, a positively charged conductive polymer, poly(diallyldimethyl ammonium chloride) (PDDA), a negatively charged polymer compound, poly(sodium 4-styrenesulfonate) (PSS), and another layer of PDDA were layered by electrostatic attraction in the order of PDDA, PSS, and finally PDDA. Then, a layer of Tyr, which was negatively charged due to pH adjustment to 7.0, was added to create a PDDA-PSS-PDDA-Tyr sensor for BPF. When the electrode sensor is exposed to a BPF solution, which is the substrate and target analyte, 4,4'-methylenebis(cyclohexa-3,5-diene-1,2-dione) is generated by an oxidation reaction with the Tyr enzyme on the electrode surface. The reduction process of the product at 0.1 V (vs. Ag/AgCl) generating 4,4'-methylenebis(benzene-1,2-diol) was measured using cyclic and differential pulse voltammetries, resulting in a change in the peak current with respect to the concentration of BPF. In addition, we compared the detection performance of BPF using an ionic liquid electrolyte as an alternative to phosphate-buffered saline, which has been used in many previous sensing studies. Furthermore, the selectivity of bisphenol S, which acts as an interfering substance with a similar structure to BPF, was investigated. Finally, we demonstrated the practical applicability of the sensor by applying it to analyze the concentration of BPF in real samples prepared in the laboratory.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.5
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• pp.221-226
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• 2010

Quartz crystal microbalance (QCM) gas sensor to detect methyl mercaptan ($CH_3SH$) gas was fabricated by depositing $TiO_2$ nanoparticles and polyelectrolyte on the electrode of QCM. The $TiO_2$/poly(sodium 4-styrenesulfonate) (PSS) thin film fabricated by a layer-by-layer self-assembly (LBL-SA) method showed a high surface area and increased the sensitivity of gas sensor. When the QCM sensors coated with triethanolamine (TEA) or ($TiO_2$/PSS) were exposed to methyl mercaptan gas (1.0 ppm), the frequency shifts of QCM with TEA casting film and $TiO_2$/PSS thin film were ca. 9 Hz and ca. 24 Hz, respectively. As the bilayer number of ($TiO_2$/PSS) increased, the frequency shift of QCM sensor with ($TiO_2$/PSS) thin film was gradually increased. In addition, the frequency shift of QCM sensor was gradually increased as the concentration of methyl mercaptan gas increased from 0.5 ppm to 2.0 ppm. In this study, the surface morphology and sensor property of QCM sensor coated with ($TiO_2$/PSS) thin film were measured.