Investigating of dielectric anisotropy and birefringence of binary liquid crystal mixtures

Abstract

Absorbance, capacitance, conductance, dielectric anisotropy and birefringence properties and splay elastic coefficient of 4’-Hexyl-4-biphenylcarbonitrile (6CB) and its mixture with 4’-Octyl-4-biphenylcarbonitrile (8CB) were investigated. The absorbance was studied using the UV-visible spectrophotometry. Capacitance, conduction and dielectric measurements for 6CB and its mixture were performed in  0-1000 kHz frequency range at the room temperature. Capacitance-voltage and capacitance-frequency changes were investigated for the mixture. Threshold voltage was determined as 2.1 V. It was seen that the capacitance suddenly damped at this voltage. Capacitance is large at lower frequencies and small at higher frequencies than 100 kHz. The conductance-voltage change was obtained for the mixture. The conduction suddenly rose at the threshold voltage. The conduction is small at lower frequencies and large at higher frequencies. Dielectric, birefringence index and splay elastic constant were investigated for 6CB/8CB mixture. The measured values of the mixture are bigger than 6CB values up to the certain frequency.

Keywords

• Electric properties,Elasticity,Optical properties,Liquid crystals

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