• 한국고분자학회지:고분자과학과기술
• /
• 제24권4호
• /
• pp.366-373
• /
• 2013

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
• /
• pp.232-234
• /
• 1996

We have investigated the effect of molecular structure of polymer of rubbed polyimide (PI) films for surface liquid crystal alignment. To obtain surface alignment effect of Polymer molecular structure, we measured the polar (out of plane-tilt) anchoring strength and surface ordering of 5CB on rubbed PI surfaces. We have found that the polar anchoring strength of 5CB is depend on the polymer molecular structure of these unidirectionally rubbed PI surfaces.

• E2M - 전기 전자와 첨단 소재
• /
• 제10권5호
• /
• pp.461-466
• /
• 1997

In this paper, we developed the new non-rubbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) light irradiation on polyimide (PI) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV light irradiation on PI surface. We successfully obtained that the pretilt angle of NLC is generated about 3.3 degree in the cell with slanted non-polarized UV light irradiation with 70 degree on PI surface, for the first time. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecular and the PI, which is broken the polymer by slanted non-polarized UV irradiation. Therefore, we concluded that the uniform LC alignment is attributed to anisotropic dispersion force due to photo depolymerization with slanted non-polarized UV light irradiation on PI surface.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1600-1602
• /
• 1996

We have investigated the anisotropic dispersion force effects for surfaces alignment of liquid crystals (LCs) on rubbed polystyrene (PS) surfaces by unidirection. In microphotographs an of the textures, we obtained the nematic (N) LCs are shown to align in both direction parallel and perpendicular to the rubbing for region up to medium rubbing, however to align in the direction perpendicular to the rubbing for strong rubbing region. We suggest that the anisotropic dispersion force is very important rather than macro-surface groove effect to uniform alignment of LCs. We also measured the temperature dependence of extrapolation length of 5CB on rubbed PS surfaces for strong rubbing. It is shown that the polar anchoring strength of 5CB is very weak on rubbed PS surface compared to the rubbed polyimide (PI) surface.

• 한국전기전자재료학회논문지
• /
• 제13권3호
• /
• pp.235-240
• /
• 2000

New photh-alignment materials based on PCEMA (poly(4-methacryloyloxylchalcone))for liquid crystal (LC) aligning were synthesized. and the electro(EO) characteristics of the photo-aligned TN-LCD were investigated. The excellent LC alignment and voltage-transmittance (V-T) characteristics for the photo-aligned TN-LCD on PCEMA surface containing more cinnamoly group can be achieved. However the reverse tilt disclinations for the photo-aligned TN-LCD on the PCEMA surface containing more OH group were observed. Consequently we suggest that the LC aligning capabilities can be increased by increasing of cinnamoly group on the PCEMA surfaces.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.178-181
• /
• 2001

The electro-optical (EO) characteristics for the twisted-nematic (TN)-liquid crystal display (LCD) photo-aligned with polarized UV exposure on various blending photopolymer surfaces were investigated. Excellent LC alignment and voltage-transmittance (V-T) characteristics for TN-LCD photo-aligned with polarized UV exposure of normal incidence on the blending Photopolymer (polyimide (PI) + PM4Ch (poly(4-methacryloyloxy chalcone))) surface containing chalcone group can be achieved. The EO performances of the TN-LCD photo-aligned on the blending photopolymer can be improved due to the photosensitivity by long side chain of the photopolymer.

• 한국전기전자재료학회논문지
• /
• 제16권3호
• /
• pp.214-218
• /
• 2003

We studied the nematic liquid crystal (NLC) aligning capabilities by the UV alignment method on a diamond like carbon (DLC) thin film surface A good LC alignment by UV exposure on the DLC thin film surface at 200${\AA}$ of layer thickness was achieved. Also, a good LC alignment by the UV alignment method on the DLC thin film surface was observed at annealing temperature of 180$^{\circ}C$. However, the alignment defect of the NLC was observed above annealing temperature of 200$^{\circ}C$. Consequently, the good thermal stability of LC alignment by the UV alignment method o the DLC thin film surface can be achieved.

• 폴리머
• /
• 제35권4호
• /
• pp.350-355
• /
• 2011

고분자의 주사슬에 광반응을 할 수 있는 phenyldiacryloyl 그룹을 가지고, 곁사슬에 액정분자와 비슷한 메조겐인 biphenyl을 에테르 결합을 통해서 도입된 가용성 광반응성 폴리아미드를 합성하였다. 합성된 폴리아미드 고분자는 0.65 dL/g의 대수점도를 가지며, 일반적인 코팅 방법으로 여러 기질의 표면에 잘 도포되는 성질을 보였다. 광반응성 폴리아미드 고분자의 화학 구조는 $^1H$ NMR과 Fourier transform infrared(FTIR) spectroscopy를 이용해서 확인하였다. 합성된 고분자의 유리전이온도는 $150^{\circ}C$까지 관측되지 않았으며, 열분해 온도는 $280^{\circ}C$로 관측되어, 열안정성이 높음을 확인하였다. 합성된 폴리아미드 고분자 박막을 비편광된 자외선을 노광시켜 노광하는 에너지에 따른 변화를 조사했을 때, 좋은 광반응성을 보였다. 광반응성 폴리아미드를 이용하여 선편광된 자외선을 노광하여 제작한 액정 셀 내에서, 액정분자들은 노광된 선편광 자외선의 electric vector 방향의 수직으로 배향되는 것이 관측되었으며, 이러한 현상은 선편광 자외선의 노광량에는 무관함을 보였다. 액정 셀 내에서 액정분자들의 pretilt angle은 선편광된 자외선의 노광량에 따라 약간의 차이를 보이며 $0.2^{\circ}$에서 $0.5^{\circ}$사이의 값을 보였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
• /
• pp.105-108
• /
• 1996

We have studied the anisotropic dispersion force effects for surfaces alignment of liquid crystals (LCs) on rubbed polystyrene (PS) surfaces by unidirection. In microphotographs of the textures, we obtained the nematic (N) LCs are shown to align in both direction parallel and Perpendicular to the rubbing for region up to medium rubbing, however to align in the direction perpendicular to the rubbing for strong rubbing legion. We suggest that the anisotropic dispersion force is very important rather than macro-surface groove effect to uniform alignment of LCs. We also measured the temperature dependence of extrapolation length of 5CB on rubbed PS surfaces for strong rubbing. It is shown that the polar anchoring strength of 5CB is very weak on rubbed PS surface compared to the rubbed polyimide (Pl) surface.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
• /
• pp.526-529
• /
• 2002

We studied the nematic liquid crystal (NLC) aligning capabilities by the UV alignment method on a diamond like carbon (DLC) thin film surface. A good LC alignment by UV exposure on the DLC thin film surface at $200\AA$ of layer thickness was achieved. Also, a good LC alignment by the UV alignment method on the DLC thin film surface was observed at annealing temperature of $180^{\circ}C$. However, the alignment defect of the NLC was observed above annealing temperature of $200^{\circ}C$. Consequently, the good thermal stability of LC alignment by the UV alignment method on the DLC thin film surface can be achieved.