• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.3025-3030
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• 2009

Novel poly(aspartic acid) derivatives conjugated with $\gamma$-amino butyric acid, GABA, moieties, and their amphiphilic analogs were synthesized and characterized. The chemical structures of these polymers were confirmed by FT-IR and $^1H$ NMR spectroscopy. Their physicochemical properties in aqueous media were characterized by electrophonetic light scattering spectrophotometry (ELS), acid-base titration, and UV-spectroscopy. In addition, the in vitro cell activity of the GABA-conjugated polymer was examined. These results indicated that GABA-conjugated poly(aspartic acid) derivatives showed cell-growth activity and nanoparticle formation of a suitable size within aqueous media. These polymers have potential application in the cosmetic and pharmaceutical fields.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.961-966
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• 2003

A quantum-chemical study of conformations and electronic structures of polyheterocyclic derivatives with vinylenediheteroatom substituents at the 3- and 4-positions was performed to search for novel blue-lightemitting conjugated polymers. Conformational potential energy curves of the polymers were constructed as a function of the helical angle (a) through semiempirical Hartree-Fock band calculations at the Austin model 1 level. It is found that poly(3,4-vinylenedioxythiophene) possesses a quite flat curve in the range of α = 51.4°- 120°. Replacing S atoms for O atoms greatly increases repulsion between the neighboring units, and thereby the units become perpendicular to one another. Because of the hydrogen bonding between O and NH, poly(3,4- vinylenedioxypyrrole) is predicted to be anti-coplanar and poly(3,4-vinylenediaminofuran) to be nearly anticoplanar. According to the modified extended Huckel band calculations, the HOMO-LUMO gaps (HLGs) of the polymers, unless the polymer chains are twisted, are close to or slightly smaller than those of their respective mother polymers. Among the polymers, poly(3,4-vinylenedioxythiophene) is presumed to be the most probable candidate for a blue-light emitter because its HLG is within the range of the electronic requirement for blue-light emitters.

• Journal of Information Display
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• 제2권2호
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• pp.45-51
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• 2001

Four types of conjugated polymers, poly(MEHPV-PV), poly(MEHPV-BPV), poly(MEHPV-AV) and poly(PZV-AV) were synthesized by Homer-Emmons reaction using potassium tert-butoxide. The Homer-Emmons reaction gave electroluminescent(EL) copolymers in good yield. Of the EL copolymers synthesized, poly(PZV-AV) containing phenothiazinylene vinylene and anthrylene vinylene as repeat unit exhibited red color in the light emitting diode(LED) which was very close to the NTSC standard red. Besides, double layer LED made with $Alq_3$ electron transport layer exhibited both enhanced emission intensity and efficiency compared to the single layer LED.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.145-148
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• 2000

In contrast to the $\pi$ -conjugated polymers which typically absorb light only in the visible spectral region, the $\sigma$-conjugated polymers can be used as efficient material absorbing light in the UV region. In this work, the electronic and optical properties of I$_2$-doped $\sigma$ -conjugated poly (methyl-phenylsilylene) (PMPSi) polymer were investigated. DC conductivity up to 1.2$\times$10$^{-4}$ S/cm was obtained by I$_2$-doping. In UV/Vis absorbance spectrum, a new peak was observed near 370 nm, which was explained by polaron model. The photoluminescence (PL) intensity decreased with increasing degree of I$_2$-doping, and the Infrared (IR) spectrum analysis revealed that the dopants are not directly coupled to the polymer, but effect motions of the methyl and phenyl groups.

• Bulletin of the Korean Chemical Society
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• 제20권6호
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• pp.677-682
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• 1999

Conjugated polycarbosilanes with diacetylene and aromatic groups of thiophene or phenylene simultaneously present in the polymer backbone such as poly[[1,4-bis(thiophenyl)buta-1,3-diyne]-alt-(dimethylsilane)], poly[[1,4-bis(thiophenyl)buta-1,3-diyne]-alt-(diphenylsilane)], poly[[1,4-bis(phenyl)buta-1,3-diyne]-alt-(dimethylsilane)],and poly[[1,4-bis(phenyl)buta-1,3-diyne]-alt-(diphenylsilane)] have been prepared. The characteristic C=C stretching frequencies appear at 2177-2179㎝-1 in the IR spectra of the polymers. The molecular weights of these polymers were detemined by GPC. All of these materials are soluble in organic solvents such as THF and chloroform, and thermally stable up to 200℃ in general without any weight loss under nitrogen. The prepared materials in THF solvent show a maximum absorption peak in the range of 334-356 nm with a molar absorptivity of 10³∼10ⁿ(n=5)L/(cm·mol) in the UV-visible absorption spectra. A maximum emission peak in the range of 403-550 nm is also observed in the fluorescence emission spectra. Both absorption and emission spectra strongly indicate that the obtained polycarbosilanes contain the new conjugated systems along the polymer main chain.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.9-10
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• 2006

Recent work in our laboratory has focused on the molecular and supramolecular engineering of conjugated polymers and oligomers for device applications, including light emitting diodes for displays and lighting, photovoltaic cells, and thin film transistors. A central finding is that the supramolecular structure of conjugated polymers can have a dominant influence on their properties and the performance of devices. Some major results include: highly efficient RGB light-emitting diodes from polymers and oligomers; high mobility n-channel polymer field effect transistors; ambipolar thin film transistors from copolymer semiconductors; and self-assembly and ambipolar charge transport in polymer nanowires.

• Macromolecular Research
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• 제15권2호
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• pp.129-133
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• 2007

Significant progress has been realized in the design and synthesis of light emitting polymers that emit over the entire visible spectrum. However, up to seventy-five percent of charge recombination events can lead to triplet states that decay non-radiatively. Following the pioneering work in the field of small molecule organic light emitting devices, it has been found that solution processible iridium polymer complexes can be used to harness the wasted triplet energy. In this paper, new results with respect to the electrophosphorescence of solution processible tethered iridium polymer derivatives are presented. Furthermore, our approaches to the design of new high triplet energy conjugated polymer hosts are also reported.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3593-3596
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• 2012

The water-soluble conjugated polymer with fluorescence quenching as a result of electrostatic interaction and aggregation was synthesized through Suzuki polymerization. The absorption and emission of anionic polymer (a-PFP) is blue shifted as compared with cationic polymer (c-PFP) although getting same backbone, and the absolute PL quantum efficiency of a-PFP in water is over 90% due to good solubility in aqueous solution. We anticipate that the fluorescence quenching of anionic and cationic polymers, with same conjugated backbone, could be shown in aqueous solution.

• 접착 및 계면
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• 제24권1호
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• pp.1-8
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• 2023

공액고분자는 유기전자소자부터 바이오메디칼 응용분야까지 다양하게 적용가능한 차세대 반도체소재이다. 하지만 낮은 수용성으로 주로 유기용매에 녹여 사용하나 최근 유기 용매의 독성과 환경 문제 이슈로 공액고분자의 수분산 나노입자화가 주목받고 있다. 본 총설에서는 나노입자가 형성되는 두 가지 원리와 이를 이용한 대표적인 공액고분자 나노입자 합성방법들 및 관련 연구들을 소개하고자 한다.

• Bulletin of the Korean Chemical Society
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• 제23권7호
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• pp.964-970
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• 2002

We synthesized three kinds of chromophores incorporating aromatic quinoline unit as a $\pi-conjugated$ bridge in order to prepare more thermally stable nonlinear optical (NLO) chromophores than general stilbene unit. The NLO poly(methylmethacrylate) copolymer, polyimides, and polyester were successfully synthesized by these corresponding quinoline-based monomers. Their physical and optical properties were investigated by thermogravimetry, gel permeation chromatography, ultraviolet-visible spectroscopy, second harmonic generation (SHG) and electro-optic (EO) measurement. All the polymers exhibited better thermal stability,however their NLO activity was a little lower than that of general stilbene-based NLO polymers. Among three kinds of polymers, the PMMA copolymer with quinoline chromophores had the largest SHG coefficient d33 value of 27 pm/V (at 1.064 $\mu\textrm{m})$ and EO coefficient r33 value of 6.8 pm/V (at 1.3 $\mu\textrm{m}$).