• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.205-208
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• 1994

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. PEO-$LiClO_4$ electrolyte with plasticizer is very unstable. Passivation phenomena in polymer electrolyte cell was described by the SPL model. The time dependance of the impedance indicates that a passivation layer grows rapidly on the Li surface. However, the growing of passivation layer on the Li surface can be restrained by addition of zeolite to the PEO electrolyte. It suggested that addition of zeoliteto to the PEO-$LiClO_4$ electrolyte effectively controls the formation of a passivation layer on Li electrode.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.199-199
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• 2011

The addition of a carbanion to ${\yen}{\acute{a}}{\yen}{\hat{a}}$-unsaturated carbonyl compounds is of importance in the C-C bond formation reactions for modern pharmaceuticals and organic synthesis. Recently, heterogeneous asymmetric catalysis became more attractive area of research because of the easy recovery and separation of the catalyst from the reaction system. Most of synthetic methods for heterogeneous catalysts were grafting or immobilization of homogeneous catalyst onto the solid supports. Trans-1,2-Diaminocyclohexane(DACH) and L-proline ligands have been enormously used as chiral ligands in several catalytic transformation under homogenous conditions. Our group prepared l-proline functionalized mesoporous silica was synthesized under acidic condition using a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer template (EO20PO70EO20, Pluronic P-123, BASF). Furthermore, we successfully directly synthesized trans-1,2 diaminocyclohexane functionalized mesoporous silica by using microwave method. The direct functionalization of chiral ligand into the framework of mesoporous materials is expected to be useful for the heterogeneous asymmetric catalysis. So, we adopt the direct synthesis of chiral ligand functionalized mesoporous silica by using thermal and microwave irradiation. Then, chiral ligand functionalized mesoporous silicas were applied to enantioselective asymmetric catalytic reactions.

• Macromolecular Research
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• 제17권3호
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• pp.174-180
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• 2009

Chemical modification of titanium/titanium oxide (Ti/$TiO_2$) substrates has recently gained a great deal of attention because of the applications of Ti/$TiO_2$-based materials to biomedical areas. The reported modification methods generally involve passive coating of Ti/$TiO_2$ substrates with protein-resistant materials, and poly(ethylene glycol) (PEG) has proven advantageous for bestowing a nonbiofouling property on the surface of Ti/$TiO_2$. However, the wider applications of Ti/$TiO_2$ based materials to biomedical areas will require the introduction of biologically active moieties onto Ti/$TiO_2$, in addition to nonbiofouling property. In this work, we therefore utilized surface-initiated polymerization to coat the Ti/$TiO_2$ substrates with polymers presenting the nonbiofouling PEG moiety and subsequently conjugated biologically active compounds to the PEG-presenting, polymeric films. Specifically, a Ti/$TiO_2$ surface was chemically modified to present an initiator for atom transfer radical polymerization, and poly(ethylene glycol) methacrylate (pEGMA) was polymerized from the surface. After activation of hydroxyl groups of poly(pEGMA) (pPEGMA) with N,N'-disuccinimidyl carbonate, biotin, a model compound, was conjugated to the pPEGMA films. The reactions were confirmed by infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle goniometry, and ellipsometry. The biospecific binding of target proteins was also utilized to generate micropatterns of proteins on the Ti/$TiO_2$ surface.

• Macromolecular Research
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• 제9권2호
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• pp.92-99
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• 2001

Silica-filled rubber compounds have slower cure characteristics than carbon black-filled ones due to the adsorption of curatives on the silica surface. Fatty acid was used as a cure activator along with zinc oxide in a sulfur cure system. Poly(ethylene glycol), PEG, was used in silica-filled rubber compounds to prevent adsorption of the curatives on the silica surface. In this study, influence of the size of fatty acid and PEG on properties of silica-filled NR compounds was investigated. It was found that the size of fatty acid and PEG affected the curt: characteristics and physical properties. The cure rate becomes faster as the PEG size increases. By increasing the size of fatty acid or PEG, the delta torque of the compound decreases while the Mooney viscosity increases. The modulus of the vulcanizate decreases with increasing the molecular weight of fatty acid or PEG. The experimental results were explained by the filler dispersion and by the prevention of the curative-adsorption on the silica surface.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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• pp.84-85
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• 2012

Poly(ethylene glycol) (PEG)는 Hydrophilic하면서 독성이 없기 때문에 약물과 관련된 연구가 많이 이루어졌다. 초기 PEGylation은 약물과 관련된 연구가 주를 이루었지만, 최근에는 PEG의 non-fouling 효과 때문에 표면에 적용하여 biomedical 장비에 세포나 단백질이 붙지 않도록 하는 개질하는 방법에 많은 연구가 진행되고 있다. Native Chemical Ligation(N.C.L.)은 단백질을 합성할 때, Protecting group을 사용하지 않고 반응을 진행시킬 수 있기 때문에 많은 주목을 받고 있다. N.C.L.은 합성한 두 물질이 Thioester와 Cysteine을 갖고 있으면, mild condition에서 amide bond를 형성하면서 반응이 쉽게 진행되기 때문에 다양한 분야에 적용할 수 있다. 이 논문에서 우리는 N.C.L.을 표면에 적용시켰으며 그 중 한 예로 표면 PEGylation진행하였다.

• Bulletin of the Korean Chemical Society
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• 제17권11호
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• pp.1004-1009
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• 1996

The interactions between a rod-coil liquid crystalline oligomer, ethyl 4-[4'-oxy-4-biphenylcarbonyloxy]-4'-biphenylcarboxylate with poly(ethylene oxide) (DP=12) (12-4) and LiCF3SO3 have been characterized by using Raman spectroscopy. Band assignments were made comparing the spectrum of 12-4 with those of the poly(ethylene glycol) monomethyl ether(PEGME) (Mw=550) and the ethyl-4'-hydroxybiphenyl-4-carboxylate (EHBPC), which are the coil and mesogen analogues, respectively. Analyzing characteristic bands of the 12-4-salt complex, we have found that the bands belonging to the coil and mesogenic units are changed in both intensities and frequencies. The spectral changes were interpreted from the viewpoint of the complexation between 12-4 and the Li+ ion. However, the possibility that the spectral changes in the mesogenic unit are not due to the complexation with the Li+ ion, but due to the conformational changes by the intercalation of nondissociated LiCF3SO3, is not ruled out.

• 전기화학회지
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• 제19권3호
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• pp.101-106
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• 2016

본 연구에서는 리튬 고분자 이차전지의 안정성과 전기화학적 특성을 향상시키기 위하여 poly(ethylen oxide)(PEO)를 lithium bis (trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl)imide 와 블렌딩-가교 법으로 복합화시켜 PEO-LiTFSI-$Pyr_{14}TFSI$ 고분자 전해질을 제조하였다. 전기화학적 산화 안정성 테스트에서 PEOLiTFSI-$Pyr_{14}TFSI$ 복합 고분자 전해질은 비록 4.4 V에서 약간의 산화곡선을 보이지만 5.7 V까지 안정하였다. PEO-LiTFSI-$Pyr_{14}TFSI$ 고분자 전해질은 온도가 증가할수록 이온전도도가 증가하며, PEO계열의 고분자 전해질의 특성상 상온에서 $10^{-6}S\;cm^{-1}$로 낮지만 $70^{\circ}C$에서는 $10^{-4}S\;cm^{-1}$까지 증가 하였다. 리튬 고분자 전지의 전기화학적 특성을 측정하기 위해 $LiFePO_4$ 양극, PEOLiTFSI-$Pyr_{14}TFSI$ 복합 고분자 전해질, 리튬 음극으로 전지를 구성하였으며 0.1 C의 전류밀도에서 방전 용량이 $30^{\circ}C$에서 $40mAh\;g^{-1}$, $40^{\circ}C$에서는 $69.8mAh\;g^{-1}$, $50^{\circ}C$에서는 $113mAhg^{-1}$을 나타내 온도의 증가에 따라 방전 용량이 증가함을 알 수 있었다. PEO-LiTFSI-$Pyr_{14}TFSI$ 복합 고분자 전해질은 $LiFePO_4$양극과 함께 50도에서 가장 우수한 충-방전 성능을 보여주었다.

• Macromolecular Research
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• 제17권12호
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• pp.969-975
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• 2009

This article describes the topical delivery and localization of budesonide through the hairless mouse skin. Two poly(ethylene oxide)-block-poly($\varepsilon$-caprolactone)-block-poly(ethylene oxide) (PEO-PCL-PEO) triblock copolymers (T 222 and T 252) having different CL:EO ratios were added in the preparation of budesonide particles stabilized with poly(vinyl alcohol) (PVA) and Tween 80 under ultrasonication. For comparison, a commercial PEO-PPO-PEO triblock copolymer (F68) was studied under the same condition. To demonstrate the effects of the triblock copolymer, the particle size of budesonide emulsion, entrapment efficiency, and in vitro release were measured and compared. The budesonide particles stabilized by the triblock copolymers had a diameter of ca. 350 nm with entrapment efficiencies of 66-76%. The In vitro release profiles of all samples showed an initial burst followed by sustained release. The skin penetration and permeation of budesonide were analyzed by using a Frantz diffusion cell. T 222 and T 252 exhibited higher total permeation amounts, but lower budesonide penetration amounts, than F68. The results suggest that the partitioning of budesonide in each skin layer can be adjusted in order to avoid skin thinning and negative immune response arising from the penetration of budesonide in blood vessels.

• 폴리머
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• 제26권6호
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• pp.785-791
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• 2002

결정성 및 무정형 고분자 전해질의 이온전도 거동에 미치는 초임계 이산화탄소 (sc$CO_2$) 유체의 영향에 대해 조사하였다. 본 연구는 폴리에테르 전해질의 이온전도도 향상에 관한 새로운 개념의 접근 방법이다. sc$CO_2$ 처리결과, 결정성 PEO 전해질의 경우 실온에서 100배 이상의, 무정형 PMEO 전해질은 9$0^{\circ}C$에서 30배 가까운 이온전도도의 상승을 나타내었다. 이는 고분자 매트릭스 내부로 $CO_2$ 분자가 침투함으로써 이온 분산효과로 캐리어 이온의 수를 증가시키고 가소화 효과로 인해 유리전이온도를 저하시켜 이온이동도를 향상시킨 결과이다.

• 폴리머
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• 제32권3호
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• pp.206-212
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• 2008

알긴산은 $\alpha$-($1{\rightarrow}4$)-L-guluronic acid(G)와 $\beta$-($1{\rightarrow}4$)-D-mannuronic acid(M)로 구성되어 있으며, 생체친화성, 무독성, 생분해성, 친수성 및 상대적으로 낮은 가격으로 인해 창상피복재나 조직공학용 지지체 및 약물운반체 등 생의학적 분야에 널리 이용하기에 적합한 물질이다. 그러나 이러한 특성을 가지는 알긴산 자체는 물에 녹지 않기 때문에 수용성인 알긴산나트륨의 형태로 많이 사용되고 있으나, 그 수용액은 매우 점도와 전도도가 높기 때문에 전기방사에 어려움이 있다. 따라서 전기방사가 가능한 수용성 고분자인 poly(ethylene oxide)(FEO)와 poly(vinyl alcohol)(PVA)을 혼합하였다. 본 연구에서는 천연 재료인 알긴산과 생체적합성이 뛰어난 수용성 고분자를 혼합하여 전기방사를 통해 나노섬유로 제조하였으며, 제조된 나노섬유는 SEM 분석 및 평균 직경 분석, XRD 분석 등을 통하여 최적 조건을 수립하였다.