Anomalous behaviour in the SmA*–SmC_A* pre‐transitional regime of a chiral swallow‐tailed antiferroelectric liquid crystal

Abstract

The temperature‐ and electric field‐dependent dielectric relaxation and polarisation of a new chiral swallow tailed antiferroelectric liquid crystal, i.e. 1‐ethylpropyl (S)‐2‐{6‐[4‐(4′‐decyloxyphenyl)benzoyloxy]‐2‐naphthyl}propionate (abbreviated as EP10PBNP), were investigated. The electric field‐induced dielectric loss spectra of EP10PBNP revealed electroclinic and anomalous dielectric behaviour in the chiral smectic A (SmA*)–chiral antiferroelectric smectic C (SmC_A*) pre‐transitional regime. From an analysis of thermal hysteresis of the dielectric constant, electric field‐induced polarisation and dielectric loss spectra, the appearance of a ferrielectric‐like mesophase is observed followed by an unstable SmC_A* phase in the SmA*–SmC_A* pre‐transitional regime.

Keywords:

• chiral swallow‐tailed antiferroelectric liquid crystal
• pre‐transitional regime
• dielectric anomaly
• electroclinic effect

Acknowledgments

The authors are grateful to Council of Scientific and Industrial Research for their financial support. The authors also acknowledge the AvH foundation for providing dielectric measuring instrument (HP4192A).