Reference : Sub-second dynamic phototuning of alignment in azodendrimer-doped nematic liquid crys...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Physics and Materials Science
http://hdl.handle.net/10993/37738
Sub-second dynamic phototuning of alignment in azodendrimer-doped nematic liquid crystal shells
English
Noh, Junghyun mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
Jampani, Venkata mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
Haba, Osamu [Yamagata University]
Yonetake, Koichiro [Yamagata University]
Takezoe, Hideo [Toyota Physical and Chemical Research Institute]
Lagerwall, Jan mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
1-Oct-2018
Journal of Molecular Liquids
Elsevier
267
Special Issue Dedicated to the Memory of Professor Y. Reznikov
197-204
Yes (verified by ORBilu)
International
0167-7322
Netherlands
[en] Nematic liquid crystal ; Azodye dendrimer ; Photoswitching of alignment ; Phase separation
[en] The alignment of nematic liquid crystal 5CB in micron-thick shells, suspended in and containing aqueous liquid phases, can be rapidly switched between radial (homeotropic) and tangential (planar) director field by doping them with a photoresponsive dendrimer with multiple azobenzene moieties in the branches. The dendrimer spontaneously segregates to the inner as well as outer shell interfaces, folding into an amphiphilic conformation irrespective of the sign of interface curvature. The branches are directed into the liquid crystal, inducing a homeotropic ground state. Upon UV irradiation, the trans-cis isomerization of azobenzene triggers immediate switching to planar alignment. The very fast realignment and the simultaneous response throughout the shell leads to an initially random planar director field, with many topological defects of both positive and negative signs becoming visible within a second of irradiation. All but two +1 defects quickly annihilate, and the remaining defect pair moves up towards the thinnest part of the shell to form the planar steady state. By illuminating with visible light the homeotropic alignment is quickly recovered. By exchanging the solvent used for assisting the dendrimer dissolution, also dynamic phase separation phenomena can be studied in the shells, revealing that the dendrimer solubility in 5CB is greater in the UV-induced cis state than in the trans ground state.
European Commission - EC
Researchers
http://hdl.handle.net/10993/37738
10.1016/j.molliq.2018.02.004
H2020 ; 648763 - INTERACT - Intelligent Non-woven Textiles and Elastomeric Responsive materials by Advancing liquid Crystal Technology
FnR ; FNR6992111 > Junghyun Noh > ULISCO > Ultrathin LIquid-crystal Shells for smart COlloids > 15/04/2014 > 14/04/2018 > 2013

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