# Miscibility Studies of Bismesogen CBnCB Forming Nematic Twist-Bend Phase with Cyanobiphenyls nCB

## TL;DR

This study investigates how the nematic twist-bend phase of bismesogens behaves when mixed with cyanobiphenyl compounds, revealing how chain length affects phase stability.

## Contribution

The paper provides new insights into the stability of the nematic twist-bend phase in mixtures with varying alkyl chain lengths.

## Key findings

- Increasing the alkyl chain length of CBnCB enhances the stability of the nematic twist-bend (NTB) phase.
- The slope of the NTB-N equilibrium line remains unchanged with increasing alkyl chain length of nCB compounds.
- XRD studies were conducted on two mixtures to analyze structural properties.

## Abstract

This work aims to determine how the nematic twist-bend phase (NTB) of bismesogens containing two rigid parts of cyanobiphenyls connected with a linking chain containing n = 7, 9, and 11 methylene groups behaves in mixtures with structurally similar cyanobiphenyls nCB, n = 4–12, 14. The whole phase diagrams are presented for the CB7CB-nCB system. For the other systems, CB9CB-nCB and CB11CB-nCB, only curves corresponding to NTB-N phase transition are presented. Based on the temperature-concentration range of the existence of NTB phase, it was established that an increase in the alkyl chain length of CBnCB causes an increase in the stability of the NTB phase. But surprisingly, an increase in the alkyl chain length of nCB compounds does not change the slope of the NTB-N equilibrium line on phase diagrams. It is slightly bigger when the nCB compound has the same length of alkyl chain as the length of the linking group of a bismesogen. XRD studies were carried out for two mixtures.