The effect of side-chain liquid crystalline concentration in liquid crystal on dielectric properties

Abstract

As liquid crystal (LC), E63 and as doping material, side-chain liquid crystalline polymer (SLCP) were used in this study. In order to observe the effect of SLCP concentration in LC on the dielectric properties in a wide range of frequency and bias voltage, SLCP was doped into E63 with 0 (pure E63), 1 and 10wt%. The bias voltage and frequency dependence of the dielectric properties of pure E63 and doped mixtures (E63/SCLP) have been investigated using the admittance spectroscopy method (C–V and G/ω–V) in the frequency range of 10kHz–10MHz at room temperature. The values of dielectric constant (ε′) and real (M′) and imaginary (M″) parts of electric modulus of the pure E63 and E63/SLCP (1 and 10%) were calculated using the measured admittance values. Moreover, dielectric anisotropy (Δε) was also obtained for each sample as a function of frequency. Results show that the values of dielectric parameters are strong functions of frequency and applied bias voltage depending on the concentration amount. Furthermore, dielectric anisotropy has negative values according to p/n type changing for each sample after a critical frequency value.