Dielectric and Optical Study of Biaxial Bent–Core Nematic Liquid Crystal

Abstract

We report the observation of biaxial nematic phase in a bent-core molecular system in which the biaxiality exists on a microscopic scale using polarizing microscopy, electro-optics and dielectric spectroscopy. An application of electric field induces a macroscopic biaxiality and therefore electro-optic switching. The observed electro-optic switching is explained in terms of the interaction of the ferroelectric clusters with the electric field. Dielectric spectra of the sample shows existence of low-frequency collective processes related to the microscopic polar clusters. The dielectric constant changes its sign from positive to negative and again to positive values.

Keywords:

• Bent-core molecules
• biaxial nematic
• dielectric relaxation
• electro-optic effects
• molecular and collective processes

Acknowledgment

The authors thank the EU Grant No. FP7-216025 BIND and SFI Grant No. RFP 06/RFP/ENE039 for funding this work.