Effect of frequency on dielectric properties of liquid crystal doped with side-chain liquid crystalline polymer

• Published in: Materials chemistry and physics 2011-10, Vol.129 (3), p.1142-1145
• Main Authors: Gokcen, M, Koysal, O
• Format: Article
• Language: English
• Subjects: A. Liquid crystals; C. Electronic characterization; D. Dielectric properties; D. Electrical properties; Dielectric constant; Dielectric loss; Dielectric properties; Electric potential; Frequency ranges; Liquid crystal polymers; Liquid crystals; Voltage
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2011.05.076

The frequency and applied bias voltage dependence of the dielectric properties and dielectric anisotropy of liquid crystal (LC) doped with side-chain liquid crystalline polymer (SLCP) mixture have been investigated using the admittance spectroscopy method ( C– V and G/ω– V) in the frequency range of 10 kHz to 10 MHz at room temperature. The liquid crystal used in this experiment is E63. The doping material used in this study is SLCP and its concentration is ensured 1 wt % in E63. Dielectric constant ( ɛ′), dielectric loss ( ɛ), dielectric loss tangent (tan δ) and real and imaginary parts of electrical modulus ( M′ and M″) of the E63/SLCP mixture was also calculated. Moreover, dielectric anisotropy (Δ ɛ) as a function of frequency was obtained. Results show that the values of the all dielectric parameters are strong functions of frequency and applied bias voltage. After a critical frequency, dielectric anisotropy has negative values according to p/n type changing.