Structure–property correlation of bicyclohexane nematic liquid crystals

Abstract

We report measurements of birefringence, dielectric anisotropy, splay and bend elastic constants of a homologous series of bicyclohexane nematic liquid crystals. These liquid crystals exhibit low birefringence and high negative dielectric anisotropy. In the nematic phase, the ratio of bend to splay elastic constant is less than 1 ($K_{33}/K_{11}\simeq 0.7$). The low birefringence, high negative dielectric anisotropy and low elastic constant ratio are discussed based on the optimised molecular structure obtained from density functional calculations.

Keywords:

• bicyclohexane nematic liquid crystals
• birefringence
• elastic constants
• density functional theory

Acknowledgements

We gratefully acknowledge support from the DST (SR/NM/NS-134/2010) and CSIR (03(1207)/12/EMR-II), DST PURSE and UPE-II. VD acknowledges UGC for fellowship. We thank Prof. W. Haase for providing CCN-mn compounds. RS acknowledges UGC for doctoral fellowship. We thank Prof. S. Mahapatra, School of Chemistry, UoH, for useful discussion.