Field-induced Optically Isotropic State in Bent Core Nematic Liquid Crystals: Unambiguous Proof of Field-induced Optical Biaxiality
The behaviour of bent core (BC) nematic liquid crystals was investigated under dc applied electric field. The optically isotropic state of a sample containing BC nematic was observed under application of low dc electric fields. The quality of the dark state when the sample was inserted between tw...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2013
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/id/eprint/5461/ http://umpir.ump.edu.my/id/eprint/5461/ http://umpir.ump.edu.my/id/eprint/5461/ http://umpir.ump.edu.my/id/eprint/5461/1/JphysDappl_Phys.pdf |
| Summary: | The behaviour of bent core (BC) nematic liquid crystals was investigated under dc applied
electric field. The optically isotropic state of a sample containing BC nematic was observed
under application of low dc electric fields. The quality of the dark state when the sample was
inserted between two crossed polarizers was found to be superb and it did not change when
rotating the sample between the polarizers. The coupling between the net molecular dipole
moment and the applied dc electric field was considered as the origin of the out-of-plane
switching of the BC molecules resulting in switching from the field-off bright state to the
field-on dark state. The field-induced optically isotropic state is an unambiguous proof of the
field-induced biaxiality in the BC nematic liquid crystal. A simple model explaining the
appearance of the isotropic optical state in BC nematics and the switching of the sample slow
axis between three mutually orthogonal directions under dc applied electric field is proposed. |
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