Investigation of thermo-electro-optic properties of some mixed nematic liquid crystals

ABSTRACT

The 6CB/8CB/8OCB liquid crystal mixture has been studied by Differential Scanning Calorimetry (DSC), polarised optic microscopy (POM), Semiconductor Characterization System, and Ultra-violet spectrophotometry (UV). DSC and POM results indicate that the 6CB/8CB/8OCB mixture exhibits liquid crystalline properties. The capacitance-voltage and conductance-voltage measurements were performed in the frequency range of 200-500 kHz and in the temperature range of 30oC–50oC. The 6CB/8CB/8OCB mixture showed an extremely large positive dielectric anisotropy. The molar absorptivity ϵ for the 6CB/8CB/8OCB mixture was calculated and found to be higher than the absorptivity values of the binary mixtures due to the alkyl chain length with H-aggregation.

KEYWORDS:

• Dielectric properties
• liquid crystals
• phase transition
• ultraviolet spectrometer

Acknowledgments

I would like to thank Prof. Dr. Şükrü Özğan for his technical assistance with POM measurements, and Assoc. Prof. Dr. Osman Pakma for his technical assistance with C–V measurements.