Structural study of helical polyfluorene under high quasihydrostatic pressure
(2013) In Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) 87(2).- Abstract
- We report on an x-ray diffraction (XRD) study of helical poly[9,9-bis(2-ethylhexyl)fluorene] (PF2/6) under high quasihydrostatic pressure and show an effect of pressure on the torsion angle (dihedral angle) between adjunct repeat units and on the hexagonal unit cell. A model for helical backbone conformation is constructed. The theoretical position for the most prominent 00l x-ray reflection is calculated as a function of torsion angle. The XRD of high molecular weight PF2/6 (M-n = 30 kg/mol) is measured through a diamond anvil cell upon pressure increase from 1 to 10 GPa. The theoretically considered 00l reflection is experimentally identified, and its shift with the increasing pressure is found to be consistent with the decreasing... (More)
- We report on an x-ray diffraction (XRD) study of helical poly[9,9-bis(2-ethylhexyl)fluorene] (PF2/6) under high quasihydrostatic pressure and show an effect of pressure on the torsion angle (dihedral angle) between adjunct repeat units and on the hexagonal unit cell. A model for helical backbone conformation is constructed. The theoretical position for the most prominent 00l x-ray reflection is calculated as a function of torsion angle. The XRD of high molecular weight PF2/6 (M-n = 30 kg/mol) is measured through a diamond anvil cell upon pressure increase from 1 to 10 GPa. The theoretically considered 00l reflection is experimentally identified, and its shift with the increasing pressure is found to be consistent with the decreasing torsion angle between 2 and 6 GPa. This indicates partial backbone planarization towards a more open helical structure. The h00 peak is identified, and its shift together with the broadening of 00l implies impairment of the ambient hexagonal order, which begins at or below 2 GPa. Previously collected high-pressure photoluminescence data are reanalyzed and are found to be qualitatively consistent with the XRD data. This paper provides an example of how the helical pi-conjugated backbone structure can be controlled by applying high quasihydrostatic pressure without modifications in its chemical structure. Moreover, it paves the way for wider use of high-pressure x-ray scattering in the research of pi-conjugated polymers. DOI: 10.1103/PhysRevE.87.022602 (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3577867
- author
- Knaapila, M. ; Konopkova, Z. ; Torkkeli, M. ; Haase, Dörthe LU ; Liermann, H. -P. ; Guha, S. and Scherf, U.
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)
- volume
- 87
- issue
- 2
- article number
- 022602
- publisher
- American Physical Society
- external identifiers
-
- wos:000315150500010
- scopus:84874535256
- pmid:23496539
- ISSN
- 1539-3755
- DOI
- 10.1103/PhysRevE.87.022602
- language
- English
- LU publication?
- yes
- id
- bda2c45d-70da-4dba-a93a-7e16ea83f7ec (old id 3577867)
- date added to LUP
- 2016-04-01 10:07:24
- date last changed
- 2022-04-27 18:47:39
@article{bda2c45d-70da-4dba-a93a-7e16ea83f7ec,
abstract = {{We report on an x-ray diffraction (XRD) study of helical poly[9,9-bis(2-ethylhexyl)fluorene] (PF2/6) under high quasihydrostatic pressure and show an effect of pressure on the torsion angle (dihedral angle) between adjunct repeat units and on the hexagonal unit cell. A model for helical backbone conformation is constructed. The theoretical position for the most prominent 00l x-ray reflection is calculated as a function of torsion angle. The XRD of high molecular weight PF2/6 (M-n = 30 kg/mol) is measured through a diamond anvil cell upon pressure increase from 1 to 10 GPa. The theoretically considered 00l reflection is experimentally identified, and its shift with the increasing pressure is found to be consistent with the decreasing torsion angle between 2 and 6 GPa. This indicates partial backbone planarization towards a more open helical structure. The h00 peak is identified, and its shift together with the broadening of 00l implies impairment of the ambient hexagonal order, which begins at or below 2 GPa. Previously collected high-pressure photoluminescence data are reanalyzed and are found to be qualitatively consistent with the XRD data. This paper provides an example of how the helical pi-conjugated backbone structure can be controlled by applying high quasihydrostatic pressure without modifications in its chemical structure. Moreover, it paves the way for wider use of high-pressure x-ray scattering in the research of pi-conjugated polymers. DOI: 10.1103/PhysRevE.87.022602}},
author = {{Knaapila, M. and Konopkova, Z. and Torkkeli, M. and Haase, Dörthe and Liermann, H. -P. and Guha, S. and Scherf, U.}},
issn = {{1539-3755}},
language = {{eng}},
number = {{2}},
publisher = {{American Physical Society}},
series = {{Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)}},
title = {{Structural study of helical polyfluorene under high quasihydrostatic pressure}},
url = {{http://dx.doi.org/10.1103/PhysRevE.87.022602}},
doi = {{10.1103/PhysRevE.87.022602}},
volume = {{87}},
year = {{2013}},
}