Photochemical reaction on the polymer layer for liquid crystal display

Shin, Dong-Myung; Song, Dong-Mee; Kim, Yong Bae

doi:10.1016/j.msec.2003.09.008

Cited by 9 publications

(3 citation statements)

References 3 publications

(1 reference statement)

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“…Thus, alignment directions likely vary. Polyimide, which introduces chalcone with a part of the longer alkyl chain or increases the ratio of the introduced chalcone, has a larger pretilt angle 80 …”

Section: Photoalignment Techniques For Lc Alignment Filmmentioning

confidence: 99%

“…First is photoanisotropy caused by azobenzene 14,21,24,25,31,32,48–61 . Second is photodimerization caused by cinnamate, coumarin, and chalcone 15–17,27,62–81 . Third is polyimide undergoing photodecomposition 82–84 .…”

Section: Introductionmentioning

confidence: 99%

“…14,21,24,25,31,32,[48][49][50][51][52][53][54][55][56][57][58][59][60][61] Second is photodimerization caused by cinnamate, coumarin, and chalcone. [15][16][17]27,[62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81] Third is polyimide undergoing photodecomposition. [82][83][84] Moreover, polyimide-based photoalignment layers can be designed with a photoreactive group as a side chain or a backbone structure, and polyimide itself can induce…”

Section: Introductionmentioning

confidence: 99%

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Photo‐isomerization, photodimerization, and photodegradation polyimides for a liquid crystal alignment layer

Sugiyama

Sato

Nagai

2022

Polymers for Advanced Techs

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We review the important features of LC orientation for the alignment layer, namely, production method, alignment mechanisms, and required properties. Photoalignment, which could eliminate the disadvantages of the rubbing method is explored. Applicable materials and techniques for photoalignment are also examined. Many materials for photoalignment layers have been proposed, but polyimide‐based materials are commonly used because of their transparency and insulation properties, which are needed for optical electronic devices. Furthermore, photoisomerization, photodimerization, and photodecomposition as photoalignment methods are reviewed, and specific photoreactive groups and alignment mechanisms are used to induce LC alignment. In summary, polyimides cause photodecomposition and have the following disadvantages; (1) requirement of relatively short‐wavelength ultraviolet (UV) irradiation, (2) difficulty in reorienting polymer chains owing to their rigid polymer matrix, and (3) low‐photo reactivities. The solutions for each disadvantage are already proposed, but the required properties should be determined during material design. Polyimide‐based materials introduced with the azobenzene and cinnamate groups are proposed and found to have the ability of fulfilling the required properties. The mechanism of polyimide photodecomposition is not fully understood. It likely has the advantage in terms of LC alignment stability because of the absence of E/Z isomerization. Therefore, the alignment mechanism and availabilities should be further explored.

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Section: Photoalignment Techniques For Lc Alignment Filmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photo‐isomerization, photodimerization, and photodegradation polyimides for a liquid crystal alignment layer

Sugiyama

Sato

Nagai

2022

Polymers for Advanced Techs

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Synthesis, characterization, and reactions of selected multichalcone derivatives

Al-Smadi

Mohammad

2009

Journal of Heterocyclic Chem

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magnified imageNew multiarm aromatic chalcone derivatives 2a, 2b, 2c, 2d were prepared through cross‐aldol condensation reaction between multiarm aromatic ketones 1a, 1b, 1c, 1d and 4‐(dimethyl amino)benzaldehyde in basic medium. The multiarm aromatic chalcones 2a and 2c were able to undergo cyclization reactions when treated with hydrazine or any of it's derivatives to yield the corresponding pyrazolines 3a and 3c that were reacted with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquenone in benzene to yield the aromatic pyrazoles 4a and 4c, respectively. J. Heterocyclic Chem., 46, 201 (2009).

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Enhanced, Perpendicular Liquid‐Crystal Alignment on Rubbed Films of a Coumarin‐Containing Polystyrene

Kang

Kwon

Kang

et al. 2007

Macro Chemistry & Physics

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We synthesized a series of polystyrene derivatives containing coumarin side groups using polymer analogous reactions. The liquid‐crystal (LC) alignment director for these polymer films was found to be perpendicular to the rubbing direction. The contrast ratio and anchoring‐energy values of these polystyrene derivatives were found to be much greater than those of polystyrene and poly(chloromethylstyrene), indicating that the coumarin side groups increase the aligning ability. For example, the anchoring energy of a polymer with 82 mol‐% of coumarin‐containing monomeric units, compared to polystyrene, is about 7 × 10−5 J · m−2 and 1 × 10−7 J · m−2, respectively.magnified image

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Photochemical reaction on the polymer layer for liquid crystal display

Cited by 9 publications

References 3 publications

Photo‐isomerization, photodimerization, and photodegradation polyimides for a liquid crystal alignment layer

Photo‐isomerization, photodimerization, and photodegradation polyimides for a liquid crystal alignment layer

Synthesis, characterization, and reactions of selected multichalcone derivatives

Enhanced, Perpendicular Liquid‐Crystal Alignment on Rubbed Films of a Coumarin‐Containing Polystyrene

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