Dielectric and electrooptical properties of hockey-stick-shaped liquid crystal with a negative dielectric anisotropy

• Published in: Current applied physics Vol. 23; pp. 8 - 14
• Main Authors: Dang, Phuc Toan, Srivastava, Anoop Kumar, Choi, E-Joon, Lee, Ji-Hoon
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2021; 한국물리학회
• Subjects: Dielectric relaxation; Hockey-stick-shaped liquid crystals; Response time; Rotational viscosity; 물리학; Rotational viscosity; Response time; Hockey-stick-shaped liquid crystals; Dielectric relaxation
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2020.12.013

We investigated dielectric properties of a hockey-stick-shaped liquid crystal (HLC). Two dielectric relaxation modes were observed at 0.91 kHz and 4.51 MHz. The low frequency relaxation modes in isotropic, smectic, and nematic phases are related to the motion of ions, collective tilt fluctuation, and rotation around the long molecular axis, respectively. Meanwhile, the high frequency relaxation modes in nematic and smectic phases was due to the rotation around the short axis of the molecules and hindered by the resistance of the ITO layers. We also examined the electrooptical response of the 5.0 wt% HLC-doped commercial nematic liquid crystal (LC) mixtures. The birefringence of the LC mixture was slightly increased, while the falling time and the rotational viscosity was decreased in the nematic phase.
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•Two dielectric relaxation modes of a hockey stick-shaped liquid crystal were found in isotropic, smectic, and nematic phases.•Dielectric relaxation strength and the relaxation frequency were measured versus temperature.•The effect of doping of hockey stick-shaped liquid crystal on the electrooptical properties of a commercial nematic liquid crystal mixture was investigated.•The response time was fastened due to the increase of dielectric anisotropy and the decrease of rotational viscosity.