Fluorinated esters with a very broad temperature range of the antiferroelectric phase

ABSTRACT

Antiferroelectricity is a desirable property of liquid crystalline materials. Therefore, we synthesised and studied two new chiral rod-like mesogens with a molecular core based on two biphenyls connected via ester linkage, with the phenyl substituted by a fluorine atom. The studied mesogens are characterised by nuclear magnetic resonance spectroscopy and mass spectrometry analysis. They have methyl heptyl in the chiral chain and exhibit an antiferroelectric phase in a very broad temperature range. We investigated their mesomorphic properties and confirmed the phase identification by differential scanning calorimetry and broad-frequency dielectric spectroscopy measurements. Additionally, we compared the studied mesogens with previously synthesised analogous materials. Two mixtures were formulated using a base mixture and new mesogens. The helical pitch of the synthesised mesogens and formulated mixtures was estimated using the selective reflection method.

Graphical abstract

KEYWORDS:

• Synthesis
• AFLCs
• helical pitch
• eutectic mixtures
• dielectric modes

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02678292.2023.2252381.

Additional information

Funding

This work was supported by the University Research Grant [UGB 22-801].