Planar-homeotropic transition observed for B₂ phase of banana-shaped thioester

Abstract

1,3-Phenylene bis{4-[(4-dodecyloxybenzoyl) sulfanyl] benzoate} (12OSOR) possessing banana-like achiral molecules has been studied by complementary methods to investigate linear dielectric as well as antiferroelectric properties of its B₂ phase. To this end, the following experimental methods were used: differential scanning calorimetry, polarizing microscopy, dielectric spectroscopy and reversal current method. As found, 12OSOR compound with bent-core molecules exhibits only B₂ phase that happens to be antiferroelectric. Dielectric spectra have been measured using the dielectric spectrometer based on Agilent 4294A impedance analyzer. The measurements have been done using HG 5 µm cells (giving homogeneous orientation) with gold electrodes. Thermal, dielectric, and electro-optic properties of 12OSOR are discussed.

Keywords:

• banana-shaped molecules
• antiferroelectric phase
• spontaneous polarization
• electro-optic effects
• dielectric relaxation
• molecular and collective processes

Acknowledgements

The authors would like to thank the State Committee for Scientific Research (KBN) for partial financial support in scope of the grant no. NN 202 076435. One of the authors (S. Wróbel) is grateful to the President of Université du Littoral Côte d’Opale for financial support during his stay in Calais as a visiting professor.