Formation of periodic zigzag patterns in the twist-bend nematic liquid crystal phase by surface treatment

ABSTRACT

Zigzag patterns were successfully generated in the twist-bend nematic (N_TB) phase of 1-(4-cyanobiphenyl-4′-yl)-6-(4-cyanobiphenyl-4′-yloxy)hexane (CB6OCB) via simple surface treatment. A detailed microscopy study using polarised optical microscopy and fluorescence confocal polarising microscopy was performed to observe the director arrangement in the zigzags, where distinctive periodic patterns were found to be aligned perpendicular to the rubbing direction. These patterns originate from the structural instability and generation of splay deformation with focal conic domain-like structures that are typically found in smectic phases, revealing that the N_TB phase has physical properties similar to those of the smectic phase. Observation of these unusual zigzag patterns in the N_TB phase opens an avenue for use of this phase in potential applications such as optical modulators and gratings.

GRAPHICAL ABSTRACT

KEYWORDS:

• Twist-bend nematic phase
• periodic liquid crystal structure
• orientation control
• surface treatment

Acknowledgements

This work was supported by a grant from the National Research Foundation (NRF) and funded by the Korean Government (MSIP) (2015R1A1A1A05000986).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by a grant from the National Research Foundation (NRF) and funded by the Korean Government (MSIP) (2015R1A1A1A05000986).