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Meridional orientation in biaxially aligned thin films of hairy-rod polyfluorene

Knaapila, Matti LU ; Hase, Thomas P. A.; Torkkeli, Mika; Stepanyan, Roman; Bouchenoire, Laurence; Cheun, Hyeun-Seok; Winokur, Michael J. and Monkman, Andrew P. (2007) In Crystal Growth & Design 7(9). p.1706-1711
Abstract
The uniaxial chain alignment and equatorial patterning of poly [9,9-bis(2-ethylhexyl)fluorene-2,7-diyl] (M-n = 29 kg/mol, M-w = 68 kg/mol) thin films atop rubbed polyimide substrates have been studied by grazing incidence X-ray diffraction. This specific molecular weight yields among the highest observed levels of chain alignment and optical anisotropy and, after thermal annealing, the sample undergoes transformation to a highly textured crystalline hexagonal phase. The two dominant equatorial orientations (i.e., types I and II crystallites) are found to have almost identical meridional orientation distributions. The X-ray deduced orientation is in quantitative agreement with that obtained by optical absorption measurements. It is also... (More)
The uniaxial chain alignment and equatorial patterning of poly [9,9-bis(2-ethylhexyl)fluorene-2,7-diyl] (M-n = 29 kg/mol, M-w = 68 kg/mol) thin films atop rubbed polyimide substrates have been studied by grazing incidence X-ray diffraction. This specific molecular weight yields among the highest observed levels of chain alignment and optical anisotropy and, after thermal annealing, the sample undergoes transformation to a highly textured crystalline hexagonal phase. The two dominant equatorial orientations (i.e., types I and II crystallites) are found to have almost identical meridional orientation distributions. The X-ray deduced orientation is in quantitative agreement with that obtained by optical absorption measurements. It is also shown that the equatorial ordering is paracrystalline in nature, and both type I and type II crystallites are similar in this respect. This equatorial scattering is superimposed on a background of a hexagonal phase polymer with a cylindrically isotropic orientation (type III). (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Crystal Growth & Design
volume
7
issue
9
pages
1706 - 1711
publisher
The American Chemical Society
external identifiers
  • wos:000249330900027
  • scopus:34748875418
ISSN
1528-7483
DOI
10.1021/cg0607295
language
English
LU publication?
yes
id
a0214be6-89bd-4bd7-ad3c-2decf9f14783 (old id 688334)
date added to LUP
2007-12-12 08:23:49
date last changed
2017-01-01 04:36:47
@article{a0214be6-89bd-4bd7-ad3c-2decf9f14783,
  abstract     = {The uniaxial chain alignment and equatorial patterning of poly [9,9-bis(2-ethylhexyl)fluorene-2,7-diyl] (M-n = 29 kg/mol, M-w = 68 kg/mol) thin films atop rubbed polyimide substrates have been studied by grazing incidence X-ray diffraction. This specific molecular weight yields among the highest observed levels of chain alignment and optical anisotropy and, after thermal annealing, the sample undergoes transformation to a highly textured crystalline hexagonal phase. The two dominant equatorial orientations (i.e., types I and II crystallites) are found to have almost identical meridional orientation distributions. The X-ray deduced orientation is in quantitative agreement with that obtained by optical absorption measurements. It is also shown that the equatorial ordering is paracrystalline in nature, and both type I and type II crystallites are similar in this respect. This equatorial scattering is superimposed on a background of a hexagonal phase polymer with a cylindrically isotropic orientation (type III).},
  author       = {Knaapila, Matti and Hase, Thomas P. A. and Torkkeli, Mika and Stepanyan, Roman and Bouchenoire, Laurence and Cheun, Hyeun-Seok and Winokur, Michael J. and Monkman, Andrew P.},
  issn         = {1528-7483},
  language     = {eng},
  number       = {9},
  pages        = {1706--1711},
  publisher    = {The American Chemical Society},
  series       = {Crystal Growth & Design},
  title        = {Meridional orientation in biaxially aligned thin films of hairy-rod polyfluorene},
  url          = {http://dx.doi.org/10.1021/cg0607295},
  volume       = {7},
  year         = {2007},
}