• Elastomers and Composites
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• 제47권4호
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• pp.282-291
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• 2012

최근 들어 광, 온도, pH, 전기, 자성, 압력 등과 같은 외부 환경의 작은 변화에도 반응하여 모양/부피가 변하거나 기계적, 광학적, 전기적, 화학적 특성 등이 가역적으로 바뀌는 스마트 소재에 대한 관심이 높아지고 있다. 이러한 스마트 소재들 중 광조사에 의해 소재의 다양한 특성을 가역적으로 제어할 수 있는 광응답 스마트 소재가 많은 관심을 받고 있다. 본 논문에서는 광에너지를 받아 기계적 에너지로 바로 전환되어 인공근육, 모터 등과 같은 액츄에이터 기능을 할 수 있는 광구동형 스마트 고분자 소재들에 대해 소개하고자 한다. 특히, 광구동형 스마트 고분자 소재 중에서도 마이크로와 매크로 스케일 변형이 가능한 아조벤젠을 함유한 비결정성 고분자, 액정 고분자, 자기 조립형 초분자에 대한 다양한 연구들에 대해 설명하고자 한다.

• 멤브레인
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• 제5권2호
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• pp.89-96
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• 1995

Azobenzene기를 가지는 인산형 양친매성 화합물의 기/액 계면에 있어서으 단분자막 거동이 $\pi-A$ 곡선 및 표면흡수스펙트라로 검토되었다. 분자간의 강한 수소결합력을 가지는 이 화합물들은 수면에 전개 후 즉시 결정화하여 단분자막 domain들을 형성한 회합체 흡수스펙트라를 나타내었다. 그러나 subphase의 조건(분자량이 큰 유가염의 첨가 및 pH의 상승)을 변화시킴에 의해 결정 domain 형성을 제어하는 것이 가능하였다. 한편, 금속이온 첨가는 인산령 양친매성 단분자막의 분재배향상태를 변화시켰다. 금속이온의 전하가 높을수록 ($1\leq2$ < 3 < 4 가), azobenzene기를 가지는 양친매성 화합물의 분자상태가 tilt된 배향성에 기인하는 장파장으로 이동한 흡수극대를 나타내었다. 이것은 서로 다른 전하를 가진 금속이온을 흡착시킴에 의해 단분자막의 분자배향성을 변화시켜, 단분자막의 집합상태 제어 가능성을 시사한다.

• 한국응용과학기술학회지
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• 제13권1호
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• pp.75-85
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• 1996

The absorption spectra of synthesis of long chain fatty acid containing azobenzene start from p-(p'-hydroxy phenyl azo)-benzoic acid was investigated by ultraviolet spectrophotometery in chloroform solvent at the various temperature. In addition, The pressure-area of the water-air interface was obtained and the LB film was fabricated onto a quartz slide and quartz crystal by conventional Langmuir-Blodgett(LB) method. The UV absorption spectra of Langmuir-Blodgett(LB) film on quartz slide and spectrum of monolayer formed on quartz crystal have been measured. Long chain fatty acid containing azobenzene are induced phtoisomerization by the application of u. v. and visible light irradiation alternatively the reversibility of phtoisomerization was more clear difference when the number of $C_{n}$ increased but, not so good at $C_{14}-azo$. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of $C_{n}$ increased. A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were induced by application of UV and visible light irradiation alternatively. So the LB film of long chain fatty acid containing azobenzene has possibility to being applied to functional molecular devices such as photomemory and light switching.

• Elastomers and Composites
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• 제52권3호
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• pp.173-179
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• 2017

Side-chain liquid crystalline polymers having polysiloxane skeletons were synthesized by a thiol-ene reaction, using two kinds of mesogenic groups: a cholesteryl group for induction into a cholesteric liquid crystal phase and a triazomesogenic group for imparting light-sensitivity. All the synthesized polymers were crystalline, except the one with a single cholesteryl group. Crystallinity, glass transition temperature, and melt transition temperature increased with increasing content of the azomesogenic group. The polymer (P-C10A0) with a single cholesteryl group has a cholesteric phase, the one (P-C0A10) with a single azomesogenic group has a smectic phase, and those with both types of mesogenic groups showed both smectic and cholesteric phases. The temperature ranges of the two liquid crystalline phases in the co-polymers were independent of the contents of the two types of mesogenic groups. The rate of photoisomerization of the light-sensitive azobenzene group in the polymer decreased with increasing azobenzene content due to steric hindrance between the azomesogenic groups.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 추계 종합학술대회 논문집
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• pp.554-557
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• 2004

수면 위의 지질 단분자는 박막 모델로서 많은 관심을 끌고 있으며, 많은 기술적인 응용법에 의해 다층의 박막 시스템을 연구하고 있다. 아조벤젠 혼합물인 아조벤젠 덴드리머의 단분자막에서 광이성화는 흡수스펙트럼과 멕스웰 변위전류법(MDC)에 의해 관찰할 수 있다. 덴드리머는 나뭇가지 모양을 닮은 고분자이며, 흡수스펙트럼에 의해 trans-to-cis 변환을 평가할 수 있다. 본 연구에서는 덴드리머의 광이성화특성에 관하여 연구하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1158-1162
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• 2005

Drug delivery systems have been developed to reduce the side toxicity of drugs by localizing them in the site of action. But it depends on the circulation of the blood and it doesn't have the function of locomotive mechanism of itself for searching for the region of disease. However, this problem could be solved by nanobot which have the locomotive function. So, we mimic the movement of cell that can move in a human body. In this paper, to polymerize the encapsulated actin within the liposome, electroporation technique is employed. In order to optimize polymerization and depolymerization of the liposome, we compare the time of polymerization and depolymerization by concentration of crown ether. we synthesis the liposome which contain azobenzene Linked crown Ether conjugated Actin protein. Azobenze linked crown ether holds the K+ ion by exposure of UV light and this disturbs the actin polymerization. In result, UV light could control the liposome growth. Finally, we could develop the liposome robot and control the growth and degeneration of the liposome by external stimuli such s UV light. The merit of the controlling by UV light doesn't need to inject proteins which induce polymerization and depolymerization of actin protein.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.41-44
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• 1999

Displacement current was generated in the pressure stimulus and light stimulus. Solution of azobenzene molecules (8A5H) have to character trans-to-cis. Pressure stimulus generate in the pressure and current. light stimulus generate in the displasement current. The Maxwell displacement current measuring technique has been applied for the investigation of azobenzene organic thin films under alternating photoirradiation with ultraviolet(360nm) and visible (450nm) light. The displacement current was generated due to the trans-to-cis photoisomerization by irradiation with ultraviolet light(λ$_1$=360 nm) Whereas the displacement current was generated in the opposite direction due to the cis-to-trans photoisomerization by irradiation with visible light(λ$_2$=450nm). As result, To show twice reaction certainly phase transition in pressure. A first range generated from 24$\AA$$^2$ to 29$\AA$$^2$and second range generated from 20$\AA$$^2$to 24$\AA$$^2$. Also, cetainfy stimulus apper low pressure and high pressure in photoirradiation. To see different every moment phase transition.

• Current Optics and Photonics
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• 제4권6호
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• pp.477-482
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• 2020

Recently, one of the authors has been reported an optically tunable fiber Bragg grating (FBG) with a photomechanical polymer. It was based on a typical FBG with a downsized diameter of 60 ㎛, coated with azobenzene-containing polymer material. Azobenzene is a well-known reversibly photomechanical stretchable material under ultraviolet (UV) light. The small part of the functional-coating region on the FBG absorbed UV light, which pulled the UV-exposed part of the grating. It was selectable as tunable FBG or tunable chirped FBG, by adjusting the position of UV exposure on the grating. As proof of concept for the tunable FBG device, the characteristics just including UV-induced center-wavelength shift and spectral-width changes of the device were reported. In this paper, we report for the first time that the microactuator makes it possible to control the spectral shape of the FBG reflection, according to the specifications (shape and intensity) of the UV beam that reaches the FBG coated with the azobenzene polymer. In addition, we provide the group-delay profiles for the chirped FBG, so that the sign of its dispersion (normal or anomalous) can be tailored by simply selecting the moving direction of the UV light's displacement in the experiment.

• 한국산학기술학회논문지
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• 제20권4호
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• pp.86-92
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• 2019

주 사슬에 다양한 조성의 아조벤젠기와 헥사메틸렌기를 갖는 고분자들을 쇼텐-바우만 반응을 이용하여 합성하고, 이들의 물성을 조사하였다. 합성된 고분자들의 화학 구조와 물리적 성질은 푸리에 적외선 분광법 (FT-IR), 핵자기공명 분광법($^1H-NMR$), 시차주사 열량 분석법(DSC), 열 중량 분석법(TGA), 편광 현미경법(POM), X-선 회절법(XRD)으로 조사되었다. 합성된 고분자들은 1.28에서 1.36 dL/g의 고유 점성도를 갖는 비교적 높은 분자량의 고분자들이 합성되었으며, 용해도 조사에 사용된 대부분의 용매에 잘 용해되지 않았다. 고분자 내의 아조벤젠기의 함량이 증가함에 따라 용융 전이온도($T_m$)가 급격히 높아졌으며, 아조벤젠 단위체의 함량이 50 mol% 이상인 경우 분해온도 이하에서 상 전이는 일어나지 않았다. 합성된 고분자들 중, MP-A3와 MP-A5는 넓은 액정 온도구간을 갖는 액정 고분자였으며, 약한 액정성을 갖는 네마틱 상을 나타냈다. 합성 고분자들의 이러한 성질의 차이는 trans 형태인 아조벤젠기의 선형성과 극성에서 비롯된 분자간력의 변화에 기인하는 것으로 판단된다.

• Journal of Information Display
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• 제2권3호
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• pp.6-12
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• 2001

Formation of intensity gratings was studied with two s-polarized (s+s) configuration in polymer liquid crystals (PLCs) containing a photochromic moiety (azobenzene) and a mesogenic unit (tolane, T-AB; cyanobiphenyl, CB-AB) by photoinduced alignment of PLCs. Remarkable differences were observed between the two PLCs. T-AB showed a faster response to the change in the diffraction intensity than CB-AB. In T-AB, alignment change took place faster than that of CB-AB. By introducing the tolane unit at the side chain, we obtained a diffraction efficiency of 30 % in the Raman-Nath regime