• Bulletin of the Korean Chemical Society
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• 제23권3호
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• pp.469-476
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• 2002

Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy. The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.109-109
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• 2006

Flexible polymers with densely grafted side chains adopt the shape of cylindrical brushes, because the steric repulsion of the side chains overcomes the entropic restoring force of the main chain. Combined light-and neutron scattering measurements elucidate the extend of main chain and side chain stretching as function of side chain length. The application of cylindrical brushes as molecular actuators in response to external stimuli which is discussed.

• BMB Reports
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• 제29권4호
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• pp.380-385
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• 1996

Ovomucoid third domain is a serine proteinase inhibitor protein which consists of 56 amino acid residues. A fifty picosecond molecular dynamics (MD) simulation was carried out for ovomucoid third domain protein with 5 $\AA$ layer of water molecules. A comparison of main chain atoms in the MD averaged structure with the crystal structure showed that most of the backbone structures are maintained during the simulation. Investigation of the intramolecular hydrogen bondings indicated that most of the interactions between main chain atoms were conserved, whereas those between side chains were reorganized for the period of the simulation. Especially, the side chain interactions around the scissile bond of reactive site P1 (Met18) were found to be more extensive for the MD structures. During the simulation, hydrogen bonds were maintained between the side chains of Glu19 and Arg21 as well as those of Thr17 and Glu19. Extensive side chain interactions observed in the MD structures may shed light on the question of why protein proteinase inhibitors are strong inhibitors for proteinases rather than good substrates.

• Macromolecular Research
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• 제17권10호
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• pp.791-796
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• 2009

An electrochemically and photochemically polymerizable monomer, 2-((2,3-dihydrothieno[3,4-b] [1,4]dioxin-2-yl)methoxy)ethyl methacrylate (EDOT-EMA), was explored for patterning of poly(3,4-ethylenedioxythiophene) (PEDOT) via side chain cross-linking. The polymer from EDOT-EMA was deposited electrochemically to produce polymeric EDOT (PEDOT-EMA), which was directly photo-patterned by UV light as the side EMA groups of PEDOT-EMA were polymerized to give cross-linked EMA (PEDOT-PEMA). Absorption and FTIR studies of the UV-exposed film (PEDOT-PEMA) indicated that the photo-patterning mainly originated from the photo cross-linking of the methacrylates in the side-chain. After irradiation of the film, the conductivity of the irradiated area decreased from $5.6{\times}10^{-3}$ S/cm to $7.2{\times}10^{-4}$ S/cm, possibly due to bending of the conductive PEDOT channel as a result of the side chain cross-linking. The patterned film was applied to a solid state electrochromic (EC) cell to obtain micro-patterned EC cells with lines up to 5 ${\mu}m$ wide.

• 공업화학
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• 제25권5호
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• pp.487-496
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• 2014

본 연구에서는 phenothiazine과 benzothiadiazole을 기반으로 하고, phenothiazine의 질소 위치에 다양한 side-chain을 치환한 고분자를 합성하였다. 합성된 고분자는 광학적, 전기화학적 분석 결과 300~700 nm에서 흡수를 보였고, -5.4 eV 정도의 이상적인 HOMO energy level를 갖는 특성을 확인하였다. 고분자와 $PC_{71}BM$을 광활성층으로 사용한 소자를 제작하였고, 측정결과 branched side-chain을 가지며 탄소수가 많은 P2HDPZ-bTP-OBT가 2.4%로 최대 광전변환효율을 갖는 것으로 확인되었다($V_{OC}$ : 0.74 V, $J_{SC}$ : $6.9mA/cm^2$, FF : 48.0%).

• KSBB Journal
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• 제11권3호
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• pp.263-269
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• 1996

유럽 주목(Taxus baccata Pendula) 의 세포배양에 서 추출한 taxol 전구체 baccatin ill를 이용하여 항암제 taxol을 반합성할 수 있었다. 유럽주목의 캘러 스배양과 현탁배양 모두에셔 baccatin ill의 생성을 확인할 수 있었으며 함량은 건조중량 기준으로 평균 0.015%(w/w)에 달하였다. Taxol의 반합성은 세포 배양에서 생성된 baccatin ill에 taxol side chain을 합성시킴으로서 가능하였다. Taxol side chain을 합 성하기 위하여 (S)-(+)-phenylglycine로부터 (-) - -N-(S)-2-hydroxy-l-phenyl ethyl)benzamide를 합성하였고 다음 단계로 (-)-N-(lS,2S)-2-hy­d droxy-l-phenyl-3-butenyl) benzamide를 합성하 였고 최종적으로 산화과정을 거쳐 taxol side chain 인 (2R,3S) - (-) -2-(1-ethoxyethoxy)-3-phenyl-3 (phenylmethanamido) propanoic acid를 얻을 수 있었다. 이러한 반합성 과정을 통하여 0.0002 % 수준의 taxol 및 0.0005 %의 관련 taxane을 합성하였다. 이와 같이 주목 세포배양을 이용한 taxol 반합성 방법은 기존의 주목 잎에서 추출한 baccatin ill를 이용하는 방법에 비하여 충분한 경제성이 있을 수 있으며 이에 따라 taxo!의 새로운 공급원의 역할 및 기타 여러 종류의 taxol 유사체의 효율적인 이용 등 앞으로 기대 효과가 크다고 본다.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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• pp.228-233
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• 2005

The protein side-chain packing problem (SCPP) is known to be NP-complete. Various graph theoretic based side-chain packing algorithms have been proposed. However as the size of the protein becomes larger, the sampling space increases exponentially. Hence, one approach to cope with the time complexity is to decompose the graph of the protein into smaller subgraphs. Some existing approaches decompose the graph into biconnected components at an articulation point (resulting in an at-most 21-residue subgraph) or solve the SCPP by tree decomposition (4-, 5-residue subgraph). In this regard, we had also presented a deterministic based approach called as SPWCQ using the notion of maximum edge weight clique in which we reduce SCPP to a graph and then obtain the maximum edge-weight clique of the obtained graph. This algorithm performs well for a protein of less than 500 residues. However, it fails to produce a feasible solution for larger proteins because of the size of the search space. In this paper, we present a new heuristic approach for the side-chain packing problem based on the maximum edge-weight clique finding algorithm that enables us to compute the side-chain packing of much larger proteins. Our new approach can compute side-chain packing of a protein of 874 residues with an RMSD of 1.423${\AA}$.

• 공업화학
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• 제10권5호
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• pp.743-747
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• 1999

비상용성인 polystyrene(PS)와 polymethacrylate(PMA)의 블렌드에서 분자간 수소결합이 가능하도록 구성고분자를 변성하였다. 공중합을 통해 hydroxystyrene 함량이 몰분율로 각각 7%, 10%, 18% 도입된 poly(styrene-co-4-hydroxystyrene) (modified polystyrene, MPS)을 합성하여 블렌드의 상용성 변화를 살펴보았다. 또한 PMA의 측쇄의 크기가 분자간 수소결합 형성에 미치는 영향을 조사하기 위하여 각각 methyl기, butyl기, hexyl기, ethylhexyl기의 측쇄를 갖는 PMA를 선정하였다. 그 결과 수산기의 함량이 증가함에 따라 분자간 수소결합 형성이 증가하였다. PMA의 측쇄의 크기에 따라 수소결합 형성 정도가 영향을 받아 상용성에 큰 차이가 나타남을 온도변화에 따른 상변화 거동을 통하여 확인하였다. 측쇄의 크기가 증가됨에 따라 입체장애 효과와 증가된 사슬의 운동성 때문에 분자간 수소결합의 형성 및 수소 결합력은 크게 감소하였다.

• Macromolecular Research
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• 제11권5호
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• pp.375-381
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• 2003

Silver salt complex membranes with glassy poly(methyl methacrylate) (PMMA) unexpectedly showed higher propylene permeance than those with rubbery poly(butyl methacrylate) (PBMA) where as neat PMMA is much less permeable to propylene than that of neat PBMA. Such unusual facilitated olefin transport has been systematically investigated by changing the side chain length of polymethacrylates (PMAs) from methyl, ethyl to butyl. The ab initio calculation showed almost the same electron densities of the carbonyl oxygens in the three PMAs, expecting very similar intensity of the interaction between carbonyl oxygen and silver ion. However, the interaction intensity decreases with the length of the alkyl side chain: PMMA > PEMA > PBMA according to wide angle X-ray scattering and FT-Raman spectroscopy. The difference in the interaction intensity may arise from the difference in the hydrophilicity of the three PMAs, as confirmed by the contact angle of water, which determines the concentrations of the ionic constituents of silver salts: free ion, contact ion pair and higher order ionic aggregate. However, propylene solubilities and facilitated propylene transport vary with the side chain length significantly even at the same concentration of the free ion, the most active olefin carrier, suggesting possible difference in the prohibition of the molecular access of propylene to silver ion by the side chains: the steric hindrance. Therefore, it may be concluded that both the hydrophilicity and the steric hindrance associated with the side chain length in the three PMAs are of pivotal importance in determining facilitated olefin transport through polymer/silver salt complex membranes.

• Elastomers and Composites
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• 제54권1호
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• pp.14-21
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• 2019

Main-chain/side-chain liquid crystalline polymers (MCSCLCPs) combined with an azobenzene group and a cholesteryl group were synthesized to impart light and temperature sensitivity to the polymer. The polymers were designed with the azobenzene unit as the mesogenic group of the main-chain and various compositions of the azobenzene and cholesteryl units as the mesogenic group of the side-chain. The chemical structures and physical properties of the synthesized polymers were investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, polarized optical microscopy, and ultraviolet-visible (UV-Vis) spectroscopy. All the MCSCLCPs were amorphous and exhibited enantiotropic liquid crystal phases; these polymers achieved the nematic phase with increasing content of the azobenzene group and exhibited the cholesteric phase with weak liquid crystallinity as the content of the cholesteryl group was increased. Furthermore, the polymers containing the azobenzene group showed photoisomerization when exposed to UV-Vis light, and the CP-A3C7 and CP-A5C5 polymers exhibited thermochromism in the temperature range of the liquid crystal phase.