상 분리에 의한 콜레스테릭 액정의 피치 변화

박한수; 김범경; 김환기; 김인선; 송기국; Hansoo Park; Beomkyung Kim; Whanki Kim; Insun Kim; Kigook Song

Polymer(Korea), Vol.30, No.2, 182-186, March, 2006

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상 분리에 의한 콜레스테릭 액정의 피치 변화

Pitch Variations in Cholesteric Liquid Crystals by Phase Separation

박한수, 김범경, 김환기, 김인선¹, 송기국 ^†

경희대학교 영상정보소재기술 연구센터
¹아이컴포넌트

Hansoo Park, Beomkyung Kim, Whanki Kim, Insun Kim¹, and Kigook Song^†

Materials Research Center for Information Display, Kyung Hee University, Yongin, Gyeonggi-do 449-701, Korea
¹I-components, Pyongtaek, Gyeonggi-do 451-805, Korea

E-mail:

초록

CLC는 주기적인 나선구조 때문에 빛을 선택적으로 반사하는 특성을 보이는데, 반사 파장대역이 넓은 CLC를 광반응에 의한 상 분리 현상을 이용하여 제조하였다. CLC 액정 셀에 의하여 반사되는 빛의 파장은 노광하는 빛의 세기가 작을수록 그리고 UV 흡수 dye의 양이 증가할수록 범위가 증가하여 초기 50 nm의 반사 파장대역을 300 nm까지 넓힐 수 있었다. 광경화된 CLC 액정 셀 내에 상 분리에 의하여 형성된 다양한 CLC 피치 분포를 SEM으로 관찰하였고, ATR-IR 실험을 이용하여 CLC 피치 분포가 넓어지는 것이 상 분리에 의한 것임을 확인하였다.

Due to their periodic helical structure, cholesteric liquid crystals (CLC) have a unique ability to selectively reflect light. CLC films reflecting a broad wavelength band were prepared by inducing a pitch gradient in CLC layers through a phase separation. The reflection bandwidth of the CLC cell was broaden as irradiation light intensity decreased and as the amount of the UV absorbing dye increased. Initial reflection bandwidth of 50 nm was broaden to 300 nm. Various pitch distributions in the CLC cell was observed using SEM and ATR-IR technique was used to prove that the pitch distributions are induced through the phase separation.

Keywords:cholesteric liquid crystal;reflective polarizer;pitch distribution;phase separation;ATR-IR

[References]

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[Referenced By]

[Related Articles]

[1] Palffy-Muhoray P, Nature, 391(6669), 745 (1998)

[2] Broer DJ, Lub J, Mol GN, Nature, 378(6556), 467 (1995)

[3] Belayen SV, Schadt M, Barnik MI, Schmitt K, J. Appl. Phys., 29, 634 (1990)

[4] Kreuzer FH, Andrejewski D, Haas W, Haberle N, Spes P, Mol. Cryst. Liq. Cryst., 199, 345 (1991)

[5] Tsai ML, Chen SH, Macromolecules, 23, 1908 (1990)

[6] Li L, Faris M, SPIE, 2873, 202 (1996)

[7] Binet C, Mitov M, Boudet A, Mol. Cryst. Liq. Cryst., 339, 111 (2000)

[8] Bunning TJ, Mather PT, Liq. Cryst., 26, 557 (1999)

[9] Mitov M, Boudet A, Sopena P, Eur. Phys. J. B, 8, 327 (1999)

[10] Li L, Faris SM, SID 96 Digest , 111 (1996)

[11] Shannon PJ, Macromolecules, 17, 1873 (1984)

[12] Broer DJ, Mol. Cryst. Liq. Cryst., 261, 513 (1995)

[13] Kwon YJ, Lee WJ, Paek SH, Kim I, Song K, Mol. Cryst. Liq. Cryst., 377, 325 (2002)

[14] Hikmet RAM, Kemperman H, Nature, 392(6675), 476 (1998)

[15] Binet C, Mitov M, J. Appl. Phys., 90, 1730 (2001)