• 제목/요약/키워드: 광이성화

검색결과 18건 처리시간 0.022초

광감응성 4-Hydroxyazobenzene 박막의 액정 배향 (Liquid Crystal Alignment by Photoreactive 4-Hydroxyazobenzene Thin Film)

  • 이원주;김환기;송기국
    • 폴리머
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    • 제29권3호
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    • pp.308-313
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    • 2005
  • 광감응성 azobenzene 그룹이 분자의 주위 환경에 따라 광이성화 반응이 변화하는 것을 in-situ UV/Vis 분광 실험법과 광학 이방성 측정법을 이용하여 조사하였다. 4-Hyhoxyazobenzene을 포함하는 필름에 광조사함과 동시에 trans-isomer와 cis-isomer 특성 피크의 세기 변화를 측정하여 azobenzene 그룹의 가역적이며 반복적인 광이성화 반응을 알수 있었다. Azobenzene 자기조립체 박막이 입혀진 기판을 액정 셀의 배향막으로 사용하여 액정의 배향을 유도하였을 때, trans-azobenzene 그룹들이 조밀한 packing을 하며 기판에 수직으로 배열한 자기조립체 구조 때문에 액정 분자들도 수직 homeotropic 배향을 하였다. 이와 같은 자기조립체 박막의 액정 셀에 UV 빛을 노광하면 azobenzene그룹이 광이 성화 반응을 일으켜 cis-isomer로 변하게 되며, 이로 인해 액정의 배향이 수직에서 수평 planar 배향으로 변함을 알 수있었다.

광이성화 유기박막의 스위칭 특성에 관한 연구 (The Study on Swtiching Characterics of Organic Film by Photoisomerization)

  • 강용철;이우선;이경섭
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1997년도 추계학술대회 논문집
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    • pp.306-308
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    • 1997
  • The Maxwell displacement current was investigated in the connection with stwiching characteristics by photoisomerization of monolayers. The displacement current was generated due to the trans-to-cis photoisomerization by irradiation with ultraviolet light( λ$_1$1=360nm). whereas the displacement current was generated in the opposite direction due to the sis-to-trans photoisomerization by irradiation with visible light( λ$_1$=450nm). The reversible displacement current generation was found to be sustained by alternative irradiation with UV light and visible light.

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폴리이미드 LB막의 광이성화 현상에 관한 연구 (A Study on the Photoisomerization of LB Films of Polyimide)

  • 박근호;변용진;송경호;박태곤
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 D
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    • pp.1882-1884
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    • 1999
  • The photoisomerization of functional polyimide was investigated in the various temperatures and UV(360nm) & visible(450nm) light irradiation. The absorption spectrum of azobenzene containing polyamic acid in a mixture of N,N-dimethylacetamide and benzene(1:1 by volume) solution was induced photoisomerization by UV and visible light irradiation. The absorption spectrum of LB films are also induced photoisomerization by UV and visible light irradiation.

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아조벤젠기를 갖는 장쇄지방산LB막의 광이성화 특성 (Properties of Photoisomerization of Organic-Ultrathin Films)

  • 김무군;박태곤;박근호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 하계학술대회 논문집 C
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    • pp.1184-1186
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    • 1995
  • The absorption spectra of synthesis of azobenzene containing long chain fatty acids were investigated by UV spectrophotometer in chloroform solution. Also, the pressure-area isotherms of the molecules on the water-air interface were obtained and the LB films were fabricated onto a quartz slides and quartz crystals by the conventional Langmuir-Blodggett(LB) method. The UV absorption spectra of Langmuir-Blodggett(LB) films on quartz slides have been measured. From these measurements, following conclusions were obtained. Azobenzene containing long chain fatty acids show a photoisomerization by irradiation of UV light and visible light alternatively. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of $C_n$ increased. Also the LB films show a photoisomerization characteristics. So the LB film of azobenzene containing long chain fatty acid has possibility to being applied to functional molecular device such as photomemory and light switching.

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광정보저장용 아조벤젠 타입 고분자에서의 광유도 복굴절 (Photo-induced birefringence on azobenzene type polymer film for optical memory)

  • 여세연;이현기;황의중;오차환;송석호;김필수;한양규
    • 한국광학회:학술대회논문집
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    • 한국광학회 2002년도 하계학술발표회
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    • pp.132-133
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    • 2002
  • 아조벤젠 고분자는 가역적 광이성화 과정에 의한 광유도 복굴절을 일으키는 물질로 광정보저장용 및 광소자용 매질로서 많은 연구가 이루어져 왔다. 일반적으로 아조벤젠 고분자는 rod-like 형태의 안정한 trans 상과 banana-like 형태의 준 안정한 cis 상의 이성체가 존재하고 이 두 이성체는 광에 의해 여기 되어 서로 다른 이성체로의 이성화가 일어나는데, 특히 막대 모양의 trans 상의 분자가 여기 시키는 광의 편광 방향에 수직으로 정렬하면서 복굴절이 유도되며 cis 상의 분자는 복굴절의 유도와 무관하다고 알려져 있다. (중략)

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아조벤젠 유기단분자의 광제어에 관한 연구 (A Study on the Light Control of Azobenzene Organic Monolayers)

  • 김성진;정헌상;이경섭
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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    • pp.139-142
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    • 2000
  • Displacement current was generated in the light stimulus. Solution of azobenzene molecules (8A5H) have to character trans-to-cis. The Maxwell displacement current measuring technique has been applied for the investigation of azobenzene organic thin films under alternating photoirradiation with ultraviolet($\lambda_1$) and visible($\lambda_2$) light. also, As laser beam(630~670nm) investigate light response. As result, ultraviolet($\lambda_1$) and visible($\lambda_2$) light see photoisomerization response, but laser beam not appear photoisomerization in current that differ wave range reagent.

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아조벤젠을 함유한 장쇄지방산과 폴리 비닐알코올간의 에스테르화 반응에 의한 폴리머의 광이성화 현상에 관한 연구 (Photoisomerization of Polymer by Esterification Reaction between Poly vinyl alcohol and Azobenzene-containing Long Chain Fatty Acids)

  • 박근호
    • 한국응용과학기술학회지
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    • 제11권1호
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    • pp.53-60
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    • 1994
  • The Synthesis of azobenzene containing long chain fatty acid and poly vinyl alcohol by esterification reaction($C_{n}-Azo-PVA$) was optimized, starting from P-(P'-hydroxy phenyl azo)-benzoic acid and the product of reaction containing azobenzene chromophores was investigated by ultraviolet spectrophotometery in toluene solvent at room temperature. In addition, UV absorption spectra of Langmmuir Blodggett (LB) film deposited on quartz plate have been measured and the structure of these compounds were ascertained by means of Ultraviolet and FT-IR. Recrystallization of reaction product in the solvent results the experimental yield obtained about 22.27% P-(P'-octadecyloxy phenyl azo)-benzoic acid-poly vinyl alcohol. Long chain azobenzene derivative-poly vinyl alcohols are induced phtoisomerization by u, v, and visible light irradiation. The LB film of azobenzene containing long chain fatty acids($C_{18}-Azo-PVA$) are possible of being applied to functional molecular devices such as photomemory and light switching.

유기박막의 외부자극 특성 (External Stimulus Properties of Organic Thin Films)

  • 강용철;이우선;박태곤;권영수;조수영;이경섭
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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    • pp.213-216
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    • 1997
  • The Maxwell displacement current was investigated in the connection with phase diagram of monolayers on a water surface. We measwed the displacement current of 8A5H monolayers on the water surface. The displacement current generated during 8A5H monolayers compression. Also, displacement current pulses were found to be generated when isomerizations were induced in 8A5H monolayers by irradiation with ultraviolet light ($lambda_1=340nm$) and visible light($lambda_2=450nm$).

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벤잘피롤린온의 광증감적 이성질화 반응 (Sensitized Photoisomerization of Benzalpyrrolinones)

  • 박용태
    • 대한화학회지
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    • 제22권6호
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    • pp.417-422
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    • 1978
  • 벤잘피롤린은 (Z-2, Z-4)을 직접 조사하거나 광증감제를 넣어 조사하니 광산소화되지 않고 광이성화 되었다. 단색광 (557nm)을 사용하여 광증감제인 로즈벤갈 (rose bengal)만을 들뜨게하여서 일어나는 벤잘피롤린은 (Z-2, Z-4 및 E-2)들의 이성화에서는 삼중상태의 벤잘피롤린온이 관여하였다.

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지방산 Langmuir-Bledgett막의 광이성화에 관한 연구 (A Study on the Photoisomerization of Langmuir-Bledgett Films of Fatty Acid)

  • 박근호
    • 한국응용과학기술학회지
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    • 제16권3호
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    • pp.193-198
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    • 1999
  • Maxwell displacement current(MDC) measuring technique has been applied on the study of monolayers of fatty acid. The displacement current was generated from monolayers on the water surface by monolayer compression and expansion. Displacement current was generated when the area per molecule was about $130{\AA}^2$. MDCs were investigated in connection with monolayer compression cycles. It was found that the current pulses were generated over the entire range of molecular area, and the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. We investigated the change in absorption spectra of the fatty acid(8A5H) monolayer LB film due to cis-trans photoisomerization. It was found that the absorption spectrum of the 8A5H LB film was induce to photoisomerization by alternate irradiation with UV and visible light irradiation.