Topological transition to rest in the electrohydrodynamics of nematics

ABSTRACT

Some nematic liquid crystals undergo electro-convective instabilities if forced by a low-frequency oscillating electric field. When the forcing amplitude is increased, a series of bifurcations occurs, which correspond to increasing disorder and reduction of the size of the electro-convective rolls. At a threshold, a transition to an electrohydrodynamic state characterised by a high density of topological defects occurs. Here, we show that in some nematic mixtures this transition is replaced by a topological transition to rest, that is, the electrohydrodynamics are quenched by the nucleation of a state that is topologically non-equivalent to the initial texture of the nematic.

GRAPHICAL_ABSTRACT

KEYWORDS:

• Nematics
• electrohydrodynamics
• topological defects
• transition

Acknowledgments

The authors thank Francesco Carbone and Kazumasa Takeuchi for valuable discussions and Eduardo D’Ippolito and Matteo Donato for measuring the dielectric anisotropies of the mixtures.

Disclosure statement

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

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02678292.2024.2386577

Additional information

Funding

G. P. thanks the Università Italo-Francese (UIF) for its support.