Synthesis, miscibility, and properties of rodlike/flexible polymer composites via in-situ rod chain formation

Kim, Y.; Ree, M.; Chang, Tai Hyun; Ha, Cong-Tu

doi:10.1007/bf00316393

Cited by 20 publications

(12 citation statements)

References 13 publications

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“…[65][66][67][68][69][70][71][72][73]95,124,125,155,156,[160][161][162][163][164][165][166][167] Such PI film surfaces need to be treated if they are to produce a uniform alignment of LC molecules with a defined range of pretilt angle values. [37][38][39][40][41][42]55,83,84,[108][109][110][111][112][113][114][115][116][117][118][119][120][121][122] At present, a rubbing process using a velvet fabric is the only technique adopted in the LC display industry to treat PI film surfaces for the mass-production of flat-panel LC display devices. This process has become the method of choice because of its simplicity and the controllability with this method of both the LC anchoring energy and the pretilt...…”

Section: Pis For Liquid Crystal Alignmentmentioning

confidence: 99%

High performance polyimides for applications in microelectronics and flat panel displays

2006

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Polyimides (PIs) exhibit excellent thermal stability, mechanical, dielectric, and chemical resistance properties due to their heterocyclic imide rings and aromatic rings on the backbone. Due to these advantageous properties, PIs have found diverse applications in industry. Most PIs are insoluble because of the nature of the high chemical resistance. Thus, they are generally used as a soluble precursor polymer, which forms complexes with solvent molecules, and then finally converts to the corresponding polyimides via imidization reaction. This complexation with solvent has caused severe difficulty in the characterization of the precursor polymers. However, significant progress has recently been made on the detailed characterization of PI precursors and their imidization reaction. On the other hand, much research effort has been exerted to reduce the dielectric constant of PIs, as demanded in the microelectronics industry, through chemical modifications, as well as to develop high performance, light-emitting PIs and liquid crystal (LC) alignment layer PIs with both rubbing and rubbing-free processibility, which are desired in the flat-panel display industry. This article reviews this recent research progresses in characterizing PIs and their precursors and in developing low dielectric constant, light-emitting, and LC alignment layer PIs.

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Section: Pis For Liquid Crystal Alignmentmentioning

confidence: 99%

High performance polyimides for applications in microelectronics and flat panel displays

2006

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“…Figure15. Variation of the pretilt angle of the LC molecules in contact with the rubbed film surface as a function of the temperature at which the rubbed film was annealed before used in the LC cell assembly.…”

mentioning

confidence: 99%

Rubbed Thin Films of Well-defined Brush Polyimides for Flat-Panel Liquid Crystal Displays: Surface Morphology, Molecular Orientation, and Liquid Crystal Alignability

Hahm

Lee

Chae

et al. 2006

High Performance Polymers

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A series of well-defined brush polyimide (PI) composed of two 4- n-alkyloxyphenyloxy bristles per repeat unit on a semi-rigid poly(4,4′-methylenyldiphenylene pyromellitimide), Cm-PMDA-MDA PIs, were synthesized and their nanoscale thin films prepared by conventional spin-coating of their soluble poly(amic acid) precursor solutions and subsequent drying and thermal imidization in a nitrogen atmosphere. All the PIs were determined to be a positively birefringent polymer. The surface morphology and molecular orientation of each PI in films before and after rubbing were investigated in detail by atomic force microscopy, optical retardation analysis, and linearly polarized infrared spectroscopy. The sequence of the rubbing-induced polymer segmental orientations was further investigated in detail. In addition, the liquid crystal alignment and pretilt ability of the rubbed PI films were examined, and their thermal stability investigated. The present study provides important information on the sequence of the polymer segmental orientations induced by rubbing and additionally the mechanisms of the alignment and pretilt of liquid crystal molecules in contact with the rubbed PI film surface.

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“…It is generally accepted that polyimide fluorescence usually arises from CTCs that form between electron donor (diamine) and electron acceptor (diimide) segment pairs [21,23,28]. Figure 7 shows the effect of silica contents on the emission wavelength and intensity of polyimide/silica composite films [8]. On increasing silica content, the wavelength was slightly redshifted and the intensity was reduced.…”

Section: Resultsmentioning

confidence: 96%

Microstructure and interface in organic/inorganic hybrid composites

Cho

2000

Polym. Adv. Technol.

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Synthesis, miscibility, and properties of rodlike/flexible polymer composites via in-situ rod chain formation

Cited by 20 publications

References 13 publications

High performance polyimides for applications in microelectronics and flat panel displays

High performance polyimides for applications in microelectronics and flat panel displays

Rubbed Thin Films of Well-defined Brush Polyimides for Flat-Panel Liquid Crystal Displays: Surface Morphology, Molecular Orientation, and Liquid Crystal Alignability

Microstructure and interface in organic/inorganic hybrid composites

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