알킬 사슬을 측쇄로 가지는 새로운 수직배향제의 합성과 특성과 관한 연구

다국어 초록 (Multilingual Abstract)

VA-LCDs is widely used for recent LCD productions owing to good viewing angle and high contrast. To apply for VA-LCDs, we have synthesized novel homeotropic alignment materials with long alkyl chain as a side chain. Polyamic acid precursors were prepared by mixing the dianhydride, diamine with side chain and diamine without side chain in 1-methyl-2-pyrrolidinone (NMP) to 12~18 wt % (mole ratio of 3:1:2). We have synthesized four kinds of diamines with alkyl chain these are dodecyl tetradodecyl, hexadecyl and octadecyl 3,5-diamino benzene. The dianhydrides are 3,3,4,4-benzophenone tetracarboxylic dianhydride (BTDA), 1,2,3,4-benzene-tetracarboxylic dianhydride (PMDA), cis-1,2,3,4-cyclopentane tetracarboxylic dianhydride (CPDA). The diamines without side chain are 4,4-oxydianilin (ODA), 4,4'-methylene-dianiline(MDA), 4,4'-(Hexafluoroisopropylidene)dianiline (6FDA). The copolyimides of 18 kinds were prepared from polyamic acid precursors by thermal imidization.
A good thermal stability of the polyimides was measured by thermogravimetric analysis (TGA). The polyimides containing BTDA and PMDA (BTDA,PMDA series PI) were thermally stable until 411~488℃,but CPDA series were thermally stable until 272~407℃.
The polyimides with dodecyl chain as a side chain (R12 type PI) generated pretilt angles of 2.5~4.5o as a rubbing depth 0.1~0.4mm. On the contrary, the polyimides with the number of alkyl chain of 14,16 and 18 (R14,R16,R18 type PI) caused pretilt angles of 65~89.4 o as a rubbing depth 0.1~0.4mm. In particular, all of the CPDA series PI, and all of the R18 type PI caused high pretilt angles of 88~89.4o as a rubbing depth 0.1~0.4mm.
All of the polyimides with octadecyl chain generated high pretilt angles (88~89. 4 o), showed good homeotropic alignment states in the fringe field that was generated by patterned electrodes.
And CPDA series PI showed a high VHR (>95%) and low RDC(<451mV).
Consequently, we could expect that these homeotropic alignment materials can be used for practical VA-LCDs.

목차 (Table of Contents)

• 목차
• List of Tables = i
• List of Figures = iii
• Abstract = iv
• 1. 서론 = 1
• 1.1. LCD 업계의 동향 = 1
• 1.2. 배향막의 연구동향 = 8
• 1.3. 연구의 목적과 개요 = 14
• 2. 이론 및 실험방법 = 18
• 2.1 고분자의 분자량 = 18
• 2.2 겔 투과 크로마토그래피 = 20
• 2.3 표면자유에너지 = 21
• 2.3.1 접촉각 = 21
• 2.3.2 표면에너지 계산 = 24
• 2.4 선경사각의 측정 = 26
• 2.4.1 결정 회전법 (crystal rotation method) = 26
• 2.4.2 편광자 회전법 (polarizer rotation method) = 30
• 2.5 열분석을 위한 TGA 측정 = 36
• 2.6 FT IR 스펙트럼 측정 = 37
• 2.7 전기광학특성 측정을 위한 Cell 제작 공정 = 37
• 2.8 Cell gap 측정 = 42
• 2.9 V T 특성 측정 = 44
• 2.10 전압 보전율 (Voltage Holding Ratio : VHR) 측정 = 45
• 2.11 잔류 DC (Residual DC) 측정 = 46
• 2.12 액정의 배향 관찰 = 47
• 3. 실험 = 48
• 3.1 사용한 시약 = 48
• 3.2 분석 기기 및 측정장비 = 49
• 3.3 합성 = 50
• 3.3.1 Diamine 화합물 합성 = 50
• 3.3.2 폴리아믹산 중합 = 55
• 4. 결과 및 고찰 = 58
• 4.1 GPC 분석 = 58
• 4.2 열무게 분석 (TGA) = 59
• 4.3 FT IR 스펙트럼 분석 = 63
• 4.4 접촉각 측정 결과 분석 = 65
• 4.5. 선경사각 (pretilt angle) 측정 = 67
• 4.6 수직배향제의 배향성 및 전기광학 측정 = 73
• 4.6.1 배향상태 관찰 = 73
• 4.6.2 VT 특성 = 76
• 4.6.3 전압 보전율 (VHR) 및 잔류 DC (Residual DC) 측정 = 80
• 5. 결론 = 84
• References = 87