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Structure-property relations of liquid crystalline gels with ABA-triblock copolymers as gelators

Title data

Pettau, Robin ; Müller, Thomas ; Khazimullin, Maxim ; Rehberg, Ingo ; Schmidt, Hans-Werner:
Structure-property relations of liquid crystalline gels with ABA-triblock copolymers as gelators.
In: Zeitschrift für Physikalische Chemie : International Journal of Research in Physical Chemistry and Chemical Physics. Vol. 226 (2012) Issue 7-8 . - pp. 645-664.
ISSN 0942-9352
DOI: https://doi.org/10.1524/zpch.2012.0284

Project information

Project financing: Deutsche Forschungsgemeinschaft
Bayerisches Staatsministerium für Wissenschaft, Forschung und Kunst

Abstract in another language

This paper reports on the influence of the structure of tailored ABA-triblock copolymers on physical gelation of the nematic liquid crystal 4'-n-pentyl-4-cyanobiphenyl (5CB), rheological properties, and the electro-optical response of the gels. The block copolymer gelators, comprised of two polystyrene A-blocks connected to a cyanobiphenyl-functionalized polyhydroxystyrene B-block, were synthesized by living anionic polymerization and functionalized by polymer analogous reactions. These block copolymers feature selective solubility. The B-block is soluble in the nematic and isotropic state of 5CB, whereas the polystyrene A-blocks are only soluble in the isotropic state. Consequently, upon cooling liquid crystalline gels are formed due to the controlled microphase-separation of the A-blocks. We show that the polymer composition and the different block lengths are important to vary the gel properties and the electro-optical response. It is confirmed that the gel formation correlates to the isotropic to nematic transition of 5CB for block copolymer gelators with sufficiently long A-blocks. Higher gel elasticity is obtained if gelators with short B-blocks are employed. The influence of the polymer network on the switching behavior of these liquid crystalline gels is investigated with respect to the electro-optical response in light scattering experiments. Intriguingly, these indicate a rearrangement of the nodes formed by the A-blocks under a strong electric field for block copolymers with short A-blocks.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties
Faculties > Faculty of Mathematics, Physics und Computer Science
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics V
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics V > Chair Experimental Physics V - Univ.-Prof. Dr. Ingo Rehberg
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry I
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry I > Chair Macromolecular Chemistry I - Univ.-Prof. Dr. Hans-Werner Schmidt
Research Institutions
Research Institutions > Research Centres
Research Institutions > Research Centres > Bayreuth Institute of Macromolecular Research - BIMF
Research Institutions > Research Centres > Bayreuth Center for Colloids and Interfaces - BZKG
Research Institutions > Collaborative Research Centers, Research Unit
Research Institutions > Collaborative Research Centers, Research Unit > FOR 608 Nichtlineare Dynamik komplexer Kontinua
Graduate Schools
Graduate Schools > Elite Network Bavaria
Graduate Schools > Elite Network Bavaria > Macromolecular Science
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 530 Physics
500 Science > 540 Chemistry
Date Deposited: 29 Jun 2015 09:05
Last Modified: 29 Jun 2015 09:05
URI: https://eref.uni-bayreuth.de/id/eprint/1193