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arXiv · 2005.07887

Studies on binary mixtures of nematic liquid crystals made of strongly polar molecules with identical cores and antagonistic orientation of permanent dipoles

Dasari Venkata Sai·Tae Hoon Yoon·Surajit Dhara
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Abstract

We report experimental studies on optical (birefringence, $\Delta n$), dielectric $(\Delta \varepsilon)$ and bend-splay elastic anisotropies ($\Delta K=K_{33}-K_{11})$ of a few mixtures of two nematic liquid crystals, namely CCH-7 and CCN-47, made of highly polar molecules with identical cores and antagonistic orientation of permanent dipoles. In particular, the polar group (-CN) attached to the bicyclohexane core of CCH-7 is oriented along the longitudinal direction whereas, in CCN-47, it is oriented along the transverse direction. We show that apart from the significant contribution to the optical and dielectric anisotropies, the antagonistic orientation of strongly polar groups plays a crucial role in determining the bend-splay elastic anisotropy. The elastic properties are explained based on a model proposed by Priest, considering the effect of intermolecular association and the resulting length-to-width ratio of the molecules.

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Dasari Venkata Sai, Tae Hoon Yoon, Surajit Dhara. 2020-05-16. Studies on binary mixtures of nematic liquid crystals made of strongly polar molecules with identical cores and antagonistic orientation of permanent dipoles. https://arxiv.org/abs/2005.07887

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