편광 자외선이 조사된 액정 디스플레이용 폴리이미드 필름의 열 안정성

김일형; 김욱수; 하기룡; Il Hyoung Kim; Wook-Soo Kim; Kiryong Ha

Polymer(Korea), Vol.26, No.4, 431-438, July, 2002

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편광 자외선이 조사된 액정 디스플레이용 폴리이미드 필름의 열 안정성

Thermal Stability of Polarized UV Exposed Polyimide Films for Liquid Crystal Display

김일형, 김욱수, 하기룡 ^†

계명대학교 화학공학과, 대구 704-701

Il Hyoung Kim, Wook-Soo Kim, and Kiryong Ha^†

Department of Chemical Engineering, Keimyung University, Daegu 704-701, Korea

E-mail:

초록

편광 푸리에 변환 적외선 분광법을 이용하여 액정 디스플레이의 배향막으로 널리 사용되는 폴리이미드 필름의 편광 자외선 조사에 따른 액정의 배향성과 열적 안정성을 연구하였다. 편광자외선이 조사된 폴리이미드의 경우, 조사된 편광자외선의 극성 방향에 평행한 폴리이미드 분자들의 우선적인 광분해 반응으로 인하여 편광자외선 조사 후 남아 있는 폴리이미드 분자들은 조사된 편광자외선 극성 방향과 수직 배향을 나타내었다. 하지만 러빙 처리된 폴리이미드 필름은 러빙 방향과 평행하게 폴리이미드 분자들의 재배향이 유도됨을 확인하였다. 또한 편광자외선이 조사된 폴리이미드 배향막이 편광자외선 조사를 통한 폴리이미드 분자들의 단편화 반응 때문에 러빙 처리된 폴리이미드 배향막 보다는 열적 안정성이 저하됨을 확인하였다.

We studied the orientation behavior and thermal stability of polyimide (PI) molecules under irradiation of polarized UV (PUV) using polarized fourier transform infrared (FTIR) spectroscopy. In the case of PUV-exposed PI films, the remaining PI molecules after photo-degradation showed molecular orientation perpendicular to the irradiated PUV polarization direction predominantly, due to the preferential degradation of PI molecules parallel to the irradiated PUV polarization direction. On the other hand, the rubbing of PI films induced reorientation of the PI molecules parallel to the rubbing direction. We also investigated the thermal stability of the alignment layers formed by rubbing and PUV irradiation on the PI films using polarized FTIR. The thermal stability of the PUV irradiated PI alignment layer is lower than that of the rubbed PI layer due to the fragmentation reaction of the PI by PUV.

Keywords:polyimide;polarized UV;liquid crystal;FTIR;orientation;thermal stability

[References]

Allen SG, "Comprehensive Polymer Science: The Synthesis, Characterization, Reactions & Applications of Polymers (First Supplement)," p. 301, Pergamon Press Ltd., New York (1992)
Yeh P, Gu C, "Optics of Liquid Crystal Displays," p. 1, John Wiley & Sons, Inc., New York (1999)
Demus D, Goodby J, Gray GW, Spiess HW, Vill V, "Handbook of Liquid Crystals," vol. 1, p. 732, Wiley-VCH, New York (1998)
Lee JW, Sung SJ, Park JK, Synth. Met., 117, 271 (2001)
Bryan-Brown GP, Sage IC, Liquid Crystals, 20(6), 825 (1996)
Shannon PJ, Gibbons WM, Sun ST, Nature, 368(6471), 532 (1994)
Lu J, deshpande SV, Gulari E, Kanick J, J. Appl. Phys., 80(9), 5028 (1996)
Lien A, John RA, Angelopoulos M, Lee KW, Takano H, Tajima K, Takenaka A, Appl. Phys. Lett., 67(21), 3108 (1995)
Sakamoto K, Arafune R, Ito N, Ushioda S, Suzuki Y, Morokawa S, J. Appl. Phys., 80(1), 431 (1996)
vanAerle NAJM, Barmentlo M, Hollering RWJ, J. Appl. Phys., 74(5), 3111 (1993)
West JL, Wang X, Ji Y, Kelly JR, SID 95 Digest, 703 (1996)
Bahadur B, Mol. Cryst. Liq. Cryst., 109(1), 1 (1984)
Morozumi S, "Liquid Crystals: Applications and Uses," ed. by B. Bahadur, vol. 1, p. 185, World Scientific Publishing Co., New Jersey (1990)
Ha KR, West JL, Mol. Cryst. Liq. Cryst., 339, 125 (1999)
Ghosh MK, Mittal KL, "Polyimides: Fundamentals and Applications," p. 18, Marcel Dekker Inc., New York (1996)
Siesler HW, J. Mol. Struct., 59, 15 (1980)
Jasse B, Koenig JL, J. Polym. Sci. B: Polym. Phys., 17, 799 (1979)
Hasegawa R, Mori Y, Sasaki H, Ishibashi M, Mol. Cryst. Liq. Cryst., 262, 77 (1995)
Ban ES, Kim YB, J. Appl. Polym. Sci., 75(14), 1728 (2000)
Hasegawa M, Horie K, Prog. Polym. Sci., 26, 259 (2001)

[Referenced By]

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[1] Allen SG, "Comprehensive Polymer Science: The Synthesis, Characterization, Reactions & Applications of Polymers (First Supplement)," p. 301, Pergamon Press Ltd., New York (1992)

[2] Yeh P, Gu C, "Optics of Liquid Crystal Displays," p. 1, John Wiley & Sons, Inc., New York (1999)

[3] Demus D, Goodby J, Gray GW, Spiess HW, Vill V, "Handbook of Liquid Crystals," vol. 1, p. 732, Wiley-VCH, New York (1998)

[4] Lee JW, Sung SJ, Park JK, Synth. Met., 117, 271 (2001)

[5] Bryan-Brown GP, Sage IC, Liquid Crystals, 20(6), 825 (1996)

[6] Shannon PJ, Gibbons WM, Sun ST, Nature, 368(6471), 532 (1994)

[7] Lu J, deshpande SV, Gulari E, Kanick J, J. Appl. Phys., 80(9), 5028 (1996)

[8] Lien A, John RA, Angelopoulos M, Lee KW, Takano H, Tajima K, Takenaka A, Appl. Phys. Lett., 67(21), 3108 (1995)

[9] Sakamoto K, Arafune R, Ito N, Ushioda S, Suzuki Y, Morokawa S, J. Appl. Phys., 80(1), 431 (1996)

[10] vanAerle NAJM, Barmentlo M, Hollering RWJ, J. Appl. Phys., 74(5), 3111 (1993)

[11] West JL, Wang X, Ji Y, Kelly JR, SID 95 Digest, 703 (1996)

[12] Bahadur B, Mol. Cryst. Liq. Cryst., 109(1), 1 (1984)

[13] Morozumi S, "Liquid Crystals: Applications and Uses," ed. by B. Bahadur, vol. 1, p. 185, World Scientific Publishing Co., New Jersey (1990)

[14] Ha KR, West JL, Mol. Cryst. Liq. Cryst., 339, 125 (1999)

[15] Ghosh MK, Mittal KL, "Polyimides: Fundamentals and Applications," p. 18, Marcel Dekker Inc., New York (1996)

[16] Siesler HW, J. Mol. Struct., 59, 15 (1980)

[17] Jasse B, Koenig JL, J. Polym. Sci. B: Polym. Phys., 17, 799 (1979)

[18] Hasegawa R, Mori Y, Sasaki H, Ishibashi M, Mol. Cryst. Liq. Cryst., 262, 77 (1995)

[19] Ban ES, Kim YB, J. Appl. Polym. Sci., 75(14), 1728 (2000)

[20] Hasegawa M, Horie K, Prog. Polym. Sci., 26, 259 (2001)