Electrooptical properties of new type fluorinated phenyl-tolane isothiocyanate liquid crystal compounds

ABSTRACT

A series of 4ʹ-(4-alkyl-phenyl)-2ʹ,6ʹ-difluorotolane isothiocyanate liquid crystal (LC) compounds were synthesised, and their phase transitions and electrooptical properties were investigated. These compounds exhibit high birefringence, about 0.47–0.52. As the number of carbon atoms in the alkyl chains increases, these LC compounds can exhibit smectic phases. When these LCs were mixed into the commercial LCs, the birefringence values of LC mixtures become higher than pure commercial LCs, and the visco-elastic coefficients of five LC mixtures are very close to each other at every test temperature. The results of response properties indicate that the compounds with a tri-fluorine substitution and n-propyl end group possess better response performance than the others. These LC compounds are particularly attractive for achieving fast response times in LC optic devices.

Graphical Abstract

KEYWORDS:

• Phenyl-tolane
• isothiocyanate liquid crystals
• high birefringence
• electrooptical property

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Science Foundation of China [61378075, 61377032, 11174274, 11174279, 61205021]; Science Foundation of State Key Laboratory of Applied Optics