액정 배향막 응용을 위한 찰콘기를 함유한 광기능성 에폭시 화합물의 합성과 특성분석 = Synthesis and characterization of the photofunctional epoxy compound containing chalcone moieties for application of the liquid crystal alignment layer

다국어 초록 (Multilingual Abstract)

Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthesized for application of the liquid crystal alignment layer. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of linearly polarized UV light. With a trace amount of cationic photoinitiator, polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization. Optical anisotropy of the thin film was investigated by using UV absorption spectroscopy either with or without cationic photoinitiator. Two kinds of photochemical reaction were employed to enhance the anisotropy using the chalcone-epoxy compound. Furthermore we have made a LC-cell which were fabricated by the chalcone-epoxy film. Photoirradiation on chalcone-epoxy film was performed before LC-cell fabrication. The nematic liquid crystal(5CB) was filled into a cell in its isotropic state by a capillary action. The extent of the LC alignment was determined by measuring the transmitted light intensity of a linearly polarized light from He-Ne laser through the LC-cell as a function of the rotation angle of LC-cell under crossed polarizers. The direction of LC alignment was determined by monitoring polarized absorbance of a dichroic dye dissolved in 5CB rotating the sample under single polarizer. And in order to measure the thermal stability of LC alignment, we have heated the chalcone-epoxy film before fabricating the LC-cell. So, the difference of LC alignment properties between with and without photoinitiator was verified

목차 (Table of Contents)

• 제1장 서론 = 1
• 제2장 이론 = 5
• II-1. 액정 = 5
• 1) 액정의 분류 = 5
• 2) 광학적 이방성(Optical Anisotropy) = 6
• 3) 유전율과 굴절률 = 6
• II-2. LCD의 주요 특성 = 9
• 1) TN-LCD의 기본 구조 = 9
• 2) 투과율-전압(T-V)특성 = 9
• 3) 콘트라스트비(Contrast Ratio: CR) = 10
• 4) 응답속도(response time) = 10
• II-3. 표면 액정 배향 기술 = 12
• 1) 수직배향법 = 12
• 2) 수평배향법 = 12
• a) 고분자막의 러빙법(Rubbing) = 12
• b) 광배향법 = 13
• II-4. [2+2] Cycloaddition = 17
• II-5. Photopoly merization = 20
• 제3장 실험 = 24
• III-1. Chalcone-epoxy 합성 = 24
• 1) 4-tetrahydrophran-2-yloxy acetophenone(Compound 1) 합성 = 24
• 2) 4,4'-dyhydroxy chalcone 합성 = 25
• 3) Chalcone-epoxy의 합성 = 25
• III-2. 기기 분석 = 26
• 1) 핵자기 공명 분광 분석(NMR spectroscopy) = 26
• 2) 가시-자외선 흡수 분광 분석(UV-Vis absorption spectroscopy) = 26
• 3) 적외선 분광분석(Infrared spectroscopy) = 27
• III-3. 광개시제 = 27
• III-4. 고분자 박막의 제조 = 29
• 1) 흡수 스펙트럼 및 이방성 측정용 고분자 박막의 제조 = 29
• 2) LC-cell의 액정 배향막용 고분자 박막의 제조 = 29
• 3) LC-cell의 액정 배향막용 수직배향 polymide (JALS-2021-R1) 박막의 제조 = 29
• III-5. LC-cell 제작을 위한 액정 배향막에 UV광 조사 = 30
• III-6. LC-cell의 제작 = 30
• III-7. 액정과 Dichroic dye의 혼합 = 31
• III-8. 고분자 필름의 광학적 이방성 측정 = 32
• III-9. Transmission 방법에 의한 액정의 배향 측정 = 33
• 1) LC-cell의 제작 = 33
• 2) Optical transmission intensity 측정 = 34
• III-10. Optical Absorbance 측정을 통한 액정의 배향 측정 = 35
• 1) LC-cell의 제작 및 열처리 = 35
• 2) Optical absorbance 측정 = 35
• III-11. 열처리 한 고분자 배향막을 이용한 LC-cell 제작 및 액정 배향 측정 = 36
• 제4장 결과 및 고찰 = 38
• IV-1. 고분자의 합성 및 특성 분석 = 38
• 1) Chalcone-epoxy의 합성 = 38
• 2) 광조사에 따른 chalcone-epoxy의 PT-IR spectrum 변화 = 43
• IV-2. 고분자막의 광학적 이방성 측정 = 46
• IV-3. LC-cell의 광학적 이방성 측정 = 53
• IV-4. Optical Absorbance 측정을 통한 액정의 배향 방향 측정 = 55
• IV-5. 열처리 한 고분자 배향막을 이용한 LC-cell 제작 및 액정 배향 측정 = 57
• 제5장 결론 = 61
• 참고문헌 = 63
• Abstract = 66