Synthesis and characterization of novel polyimides bearing a side chain composed of stilbene mesogen and undecyl spacer and the alignment ability of nematic liquid-crystal molecules
Jh. Park et al., Synthesis and characterization of novel polyimides bearing a side chain composed of stilbene mesogen and undecyl spacer and the alignment ability of nematic liquid-crystal molecules, J POL SC PC, 39(10), 2001, pp. 1800-1809
Citations number
29
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
Four different polyimides with side chains containing undecyl spacers and 4
-fluorostilbene mesogen end groups were prepared, and their structures and
the controllability of the liquid-crystal (LC) alignment with rubbing were
investigated. From X-ray scattering and differential scanning calorimetry d
ata, pyromellitic dianhydride (PMDA)-, benzophenone-3,3 ' ,4,4 ' -tetracarb
oxylic dianhydride (BTDA)-, and 4,4 ' -oxydi(phthalic anhydride) (ODPA)-bas
ed polyimides were shown to have layered structures and short-range orderin
g. Pretilt angles of LCs on the rubbed surfaces were 1-9 degrees, depending
on the rubbing density and backbone. In particular, the long undecyl space
rs caused the mesogenic stilbene end groups to lie next to the main chain,
resulting in a reduction in the pretilt angles. (C) 2001 John Wiley & Sons,
Inc.