Mixing Twist-Bend and Ferroelectric nematic liquid crystals

TL;DR

This study explores the phase behavior and physical properties of binary mixtures of twist-bend and ferroelectric nematic liquid crystals, revealing their incompatibility and unique phase transition characteristics.

Contribution

It provides the first experimental analysis of the phase diagram and physical properties of Ntb and NF liquid crystal mixtures, highlighting their incompatibility.

Findings

Phase transition temperatures decrease and vanish in some compositions.

Critical behavior observed in birefringence above N-Ntb transition.

Distinct differences in splay elastic constant behavior compared to pure materials.

Abstract

Twist-bend (Ntb) and ferroelectric (NF) nematic liquid crystals exhibit several novel effects and new physical properties. The question of what happens in binary mixtures is interesting as a matter of curiosity and pure science. Here, we report experimental studies on the phase diagram and some physical properties of binary mixtures of the above-mentioned nematic liquid crystals. Both N-Ntb and N-NF phase transition temperatures and the corresponding enthalpies decrease significantly and eventually, these transitions disappear in some intermediate compositions. Temperature dependent birefringence above the N-Ntb phase transition temperature shows critical behaviour, and the critical range of the tilt fluctuations becomes wider in the mixtures. The magnitudes and the temperature dependence of the splay elastic constant of the mixtures' high-temperature nematic (N) phase strikingly differ from that of the pristine twist-bend and ferroelectric nematic liquid crystals. The study shows that Ntb and NF liquid crystals are incompatible.