Effects of thiophene-based mesogen terminated with branched alkoxy group on the temperature range and electro-optical performances of liquid crystalline blue phases

ABSTRACT

A series of symmetrically thiophene-based bent-shaped molecules with branched terminal was synthesised and characterised. Then, their effects as dopants on the blue phase (BP) range of the chiral nematic liquid crystal (N*LC) host were investigated. It was found that the bent-shaped dopants with branched terminal had better miscibility in LC host than the bent-shaped dopants with straight terminal, and contributed to induce BP and enhance the BP temperature range, with the maximum BP temperature range about 20.4°C. Besides, the electro-optical (E-O) performances of the blue phase liquid crystal doped with Th-BC6 (a bent-shaped dopant with the widest induced BP range in N*LC) were also explored. It was found that the drive voltage reduced first and then increased with the doping amount of Th-BC6 increasing. When the doping amount of Th-BC6 was about 15 wt%, the hysteresis could be strikingly reduced.

GRAPHICAL ABSTRACT

KEYWORDS:

• Blue phase
• bent-shaped molecules
• liquid crystal
• branched terminal
• electro-optical performances

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

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Additional information

Funding

This work was supported by the Major Project of International Cooperation of the Ministry of Science and Technology [grant number 2013DFB50340], the National Natural Science Foundation of China [grant numbers 61370048, 51333001, 51173017, 51203011, 51103010]; the Fundamental Research Funds for the Central Universities [grant number FRF-TP-14-013A2].