• Journal of the Korean Chemical Society
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• v.39 no.8
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• pp.666-671
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• 1995

The conformational properties of poly(ethylene oxide) (PEO) in aqueous solutions are studied by viscometry with respect to the water structure perturbing capabilities of a series of urea solutes at $16^{\circ}C$, and experiments for the effect of amounts of urea and methylurea on PEO at 16 and $25^{\circ}C$ are also performed. The results show that the chain expansion, by ureas, of PEO of $1.0{\times}10^5$ molecular weight at $16^{\circ}C$ is similar to that of PEO of $8.0{\times}10^3$ molecular weight at $25^{\circ}C$ with respect to the water structure perturbation. Urea and methylurea make the PEO chain expand by the perturbation of water structure around PEO and by the hydrophobic interaction between methylurea and PEO, respectively. PEO of $1.0{\times}10^5$ molecular weight has hydrophobic sites on it, which are roughly classified into two parts; one is the inner hydrophobic groups which can interact between themselves (intramolecular hydrophobic interaction) and prevails at $16^{\circ}C$, and the other is the outer, exposed hydrophobic groups which can interact with the added hydrophobic solute (intermolecular hydrophobic interaction) and prevails at $25^{\circ}C.$

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.3-6
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• 2003

In this work, poly(ethylene oxide) nanofibers were fabricated by electrospinning to prepare nanofibers-reinforced composites. And the PEO powders-impregnated composites were also prepared to compare with physicochemical properties of nanofibers-reinforced composites. Morphology and fiber diameter of PEO nanofibers were determined by SEM observation. Mechanical interfacial properties of the composites were investigated in fracture toughness tests and interlaminar shear strength (ILSS) test. As a result, the fiber diameter decreased in increasing applied voltage. However the optimum condition for the fiber formation was 15 ㎸, resulting from increasing of jet instability at high voltage and the prepared PEO nanofibers were useful in fiber reinforced composites. The PEO-based nanofibers-reinforced composites showed an improvement of fracture toughness factors ($K_{IC} and G_{ IC}$) and ILSS, compared to the composites impregnated with PEO powders. These results were noted that the nanofibers had higher specific surface area and larger aspect ratio than those of the powder, which played an important role in improving the mechanical interfacial properties of the composites.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.465-469
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• 2011

In this study, poly(ethyleneoxide) and poly(ethylene imine) polymer blends containing fumed silica fillers were studied in order to enhance the ion conductivity and interfacial properties. Lithium perchlorate ($LiClO_4$) as a salt, and silica($SiO_2$) as the inorganic filler were introduced into the polymer composite electrolyte composites and the composites were examined to evaluate their ionic conductivity for a possibility test of electrolyte application. As the diameter of semicircle in an impedance test became smaller, ionic conductivity of composite electrolytes had been enhanced by addition of 20 wt% silica filler. However, the conductivity was not greatly changed over 20 wt% content because the silica was sufficiently saturated in the polymer electrolytes. Diffraction peaks of PEO became weaker with the addition of inorganic fillers using XRD analysis. It showed that a crystallinity was proportionally reduced by increasing filler contents. The morphology of composite electrolyte films has been investigated by SEM. The heterogeneous morphology which silica was evenly dispersed by the strong adhesion of PEI was shown at higher contents of silica.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.302-302
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• 2006

Nanoaggregates of triple hydrophilic block copolymers comprised of poly(ethylene oxide), poly(sodium 2-acrylamido)-2-methylpropanesulfonate), and poly(methacrylic acid) (PEO-PAMPS-PMAA) and the cationic surfactant, dodecyltrimethylammonium chloride (DTAC) have been fabricated. The formation of $^{\circ}^{\circ}$the nanoaggregates is based on electrostatic interaction of sulfonate and carboxylate groups of PAMPS and PMAA blocks with the cationic surfactant, which results in insolubilization of these blocks. The formation of micelle is observed by dynamic light scattering measurements. Binding of DTAC to the anionic blocks of PEO-PAMPS-PMAA is confirmed by electrophoresis measurements.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.199-207
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• 2022

Lithium-sulfur batteries (LSBs) have emerged as a promising alternative to lithium-ion batteries (LIBs) owing to their high energy density and economic viability. In addition, all-solid-state LSBs, which use solid-state electrolytes, have been proposed to overcome the polysulfide shuttle effect while improving safety. However, the high interfacial resistance and poor ionic conductivity exhibited by the electrode and solid-state electrolytes, respectively, are significant challenges in the development of these LSBs. Herein, we apply a poly (ethylene oxide) (PEO)-based composite solid-state electrolyte with oxide Li₇La₃Zr₂O₁₂ (LLZO) solid-state electrolyte in an all-solid-state LSB to overcome these challenges. We use an electrochemical method to evaluate the degradation of the all-solid-state LSB in accordance with the carbon content and loading weight within the cathode. The all-solid-state LSB, with sulfur-carbon content in a ratio of 3:3, exhibited a high initial discharge capacity (1386 mAh g^-1), poor C-rate performance, and capacity retention of less than 50%. The all-solid-state LSB with a high loading weight exhibited a poor overall electrochemical performance. The factors influencing the electrochemical performance degradation were revealed through systematic analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1405-1407
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• 2009

We prepared polystyrene-b-poly(2-vinyl pyridine) (PSb-P2VP) lamellar films which is hydrophobic block-hydrophilic polyelectrolyte block polymer have 57 kg/mol-b-57 kg/mol. The result of UV-visible absorption spectra supported that effect of poly(ethylene oxide) on the band gap tuning of PS-P2VP photonic gel like salt effect.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.556-564
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• 2018

In this study, polyethylene oxide (PEO)/polyethylene-co-vinyl acetate (EVA)/multi-walled carbon nanotube (MWCNT)-COOH composite membranes were prepared by adding 1, 2, 3, and 5 wt% of MWCNT-COOH to PEO/EVA respectively. The gas permeation properties of $N_2$, $O_2$ and $CO_2$ at $30^{\circ}C$ and 4~8 bar pressure were investigated. In each PEO/EVA/MWCNT-COOH composite membranes, the permeability of $CO_2$ increased with increasing the pressure, but the permeability of $N_2$ and $O_2$ were independent of the feeding pressure. As the MWCNT-COOH content increased, the $CO_2$ permeability increased and then decreased above 2 wt% MWCNT-COOH content. The 2 wt% MWCNT-COOH composite membrane exhibited a $CO_2/N_2$ selectivity of 77.8 and a $CO_2$ permeability of 84 barrer at 8 bar. The high $CO_2/N_2$ selectivity and $CO_2$ permeability were due to the high affinity between the quadrupolar $CO_2$, polar ether groups of PEO, and the polar ester groups of EVA. Additionally, the strong affinity between $CO_2$ and the -COOH groups on the MWCNT surface contributed to the high permeability of $CO_2$.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.519-523
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• 2006

Poly(dimethyl siloxane) (PDMS) has been employed as a microchip material for DNA separation in microfluidic condition. Different sieving molecules such as cellulose derivatives having glucose building block (methyl cellulose (MC), hydroxyethyl cellulose (HEC), and hydroxypropyl methyl cellulose (HPMC)) and polyethylene oxide (PEO) having linear (ring-opened ethylene oxide) unit were used and their performance was compared in terms of separation efficiency and resolution. In general, PEO showed better separation performance than cellulose derivatives probably due to the nature of linear shape polymer conformation. It was possible to perform at least 15 consecutive running with 1.2% PEO at the electric field strength around 200 V/cm. Fast analysis of the standard $\Phi$X 174 RF DNA/Hae III (less than 130s) was obtained with the number of the theoretical plate around 250,000/m. Our PMDS microchip was applied to the measurement of CAG repeat number, which is related to male infertile disease.

• Bulletin of the Korean Chemical Society
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• v.19 no.9
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• pp.962-967
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• 1998

Block copolymers consisting of poly(rbenzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part were synthesized and characterized. Polymeric micelles of the block copolymers (abbreviated GEG) were prepared by a dialysis method. The GEG block copolymers were associated in water to form polymeric micelles, and the critical micelle concentration (CMC) values of the block copolymers decreased with increasing PBLG chain length in the block copolymers. Transmission electron microscopy (TEM) observations revealed polymeric micelles of spherical shapes. From dynamic light scattering (DLS) study, sizes of polymeric micelles of GEG-1, GEG-2, and GEG-3 copolymer were 106.5±59.2 nm, 79.4±46.0 nm, and 37.9±13.3 nm, respectively. The drug loading contents of GEG-1, GEG-2 and GEG-3 polymeric micelles were 12.6, 11.9, and 11.0 wt %, respectively. These results indicated that the drugloading contents were dependent on PBLG chain length in the copolymer; the longer the PBLG chain length, the more the drug-loading contents. Release of norfloxacin (NFX) from the nanoparticles was slower in higher loading contents of NFX than in lower loading contents due to the hydrophobic interaction between PBLG core and NFX.

• Macromolecular Research
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• v.15 no.4
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• pp.337-342
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• 2007

The n-butyllithium-initiated ring-opening polymerization of ethylene oxide, in a mixture of benzene and dimethylsulfoxide (DMSO), between $25-45^{\circ}C$, with potassium tert-butoxide, is a useful and powerful method to control the molecular weight as well as achieve a quantitative chain-end functionalization yield of the resulting polymeric alkoxide via a one pot synthesis. The molecular weight of the product could be controlled by adjusting the ratio of grams of monomer to moles of initiators, such as n-butyllithium ([n-BuLi]) and potassium t-butoxide ([t-BuOK]). The yields for the macromonomer and ${\omega}-brominated$ poly(ethylene oxide) (PEO) were quantitative in relation to the chain-end functionalizations of the polymeric alkoxide formed. The resulting products were characterized by a combination of $^1H-NMR$ spectroscopic and size exclusion chromatographic analyses.