New multi-fluorinated benzofuran liquid crystals with large dielectric anisotropy and improved solubility

ABSTRACT

Multi-fluorinated liquid crystal compounds with benzofuran core were synthesised and their structures were identified using ¹ H NMR, ¹³ C NMR and mass spectra. Thermal analysis shows that further fluorination of the central benzene leads to a significant decrease in melting point and broadening of the nematic temperature range. Physical property test reveals that the compounds with tetrafluoro substituent have large dielectric anisotropy, high birefringence, and improved solubility in the host mixtures. The optimal geometry, polarisability and dipole moment of liquid crystal molecules were calculated by density functional theory, and the experimental results are explained. The new compounds show an excellent application of prospects in liquid crystal display.

GRAPHICAL ABSTRACT

KEYWORDS:

• Fluorinated liquid crystal
• benzofuran
• dielectric anisotropy
• birefringence
• rotational viscosity
• solubility
• DFT

Disclosure statement

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

Additional information

Funding

This work is supported by the Key Research and Development Program of Shaanxi [Program No. 2019ZDLGY04-06, 2020GY-272, 2021GY-228].