Rubbed thin films of well-defined brush polyimides for flat-panel liquid crystal displays: Surface morphology, molecular orientation, and liquid crystal alignability
- Title
- Rubbed thin films of well-defined brush polyimides for flat-panel liquid crystal displays: Surface morphology, molecular orientation, and liquid crystal alignability
- Authors
- Hahm, SG; Lee, SW; Suh, J; Chae, B; Bin Kim, S; Lee, SJ; Lee, KH; Jung, JC; Ree, M; 이문호
- Date Issued
- 2006-01
- Publisher
- SAGE PUBLICATIONS LTD
- Abstract
- 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.
- Keywords
- brush polyimide; semi-rigid polyimide backbone; bristle; rubbing; polymer segmental orientation; orientation sequence; FTIR; two-dimensional correlation analysis; liquid crystal alignment; pretilt angle; DIETHYL ESTER) PRECURSORS; RESIDUAL-STRESS BEHAVIOR; ATOMIC-FORCE MICROSCOPY; FULLY RODLIKE BACKBONE; SIDE-CHAIN LENGTHS; AROMATIC POLYIMIDES; ALIGNMENT PROPERTIES; PHOTOSENSITIVE POLYIMIDE; ALTERNATING COPOLYIMIDES; SEGMENTAL REORIENTATIONS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/23783
- DOI
- 10.1177/0954008306068117
- ISSN
- 0954-0083
- Article Type
- Conference
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