Spontaneously modulated chiral nematic structures of flexible bent-core liquid crystal dimers

ABSTRACT

We report the induction of spontaneously undulated chiral nematic structures of liquid crystal (LC) dimers with rigid aromatic molecular arms linked by flexible chains with an odd number of carbons. When a small amount of chiral dopants (CD) are added to the dimers, we find the formation of different stripe textures on cooling 4–10 μm films in the nematic phase. The temperature where the stripes form depends on the film thickness and the direction of the stripes depends on the CD concentrations. We show that the experimentally observed stripes are due to undulation instabilities that spontaneously form as a result of the anomalously small bend elastic constant that prefers director bend instead of twist deformation, the opposite of the situation in usual cholesteric LCs.

GRAPHICAL ABSTRACT

KEYWORDS:

• Chiral dimers
• textures
• modulated structures
• elasticity

Acknowledgements

This work was financially supported by NSF DMR: [Grant Number 1307674]. The KA materials were provided by O. Parri.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by NSF DMR: [Grant Number 1307674]. The KA materials were provided by O. Parri.