Bipolar to toroidal configuration transition in liquid crystal droplets

ABSTRACT

Liquid crystal (LC) droplets dispersed in isotropic media are of significant interest for scientific community and great importance for industries. The confinement can generate many fascinating LC director configurations and enable important practical applications. With tangential anchoring condition at the droplet surface, theoretically there are several possible configurations: bipolar, twisted bipolar, escaped toroidal, toroidal and so on. Bipolar configuration is usually observed in droplets made from common LCs while the toroidal configuration is rarely observed and it is hard to create especially in thermotropic LCs. Their realisations depend on the splay, bend and twist elastic constants ratio, and anchoring condition of the LC and polymer interface. We constructed thermotropic LCs with abnormally small bend elastic constants, with which stable toroidal configuration were successfully created. We provide a brand new method to create toroidal droplet by simply varying the bend elastic constant. We observed the transition from bipolar configuration to toroidal configuration. We performed a detailed study of the texture of toroidal droplets.

GRAPHICAL ABSTRACT

KEYWORDS:

• Toroidal droplet
• elastic constant
• configuration transition
• droplet texture
• liquid crystal dimer

Acknowledgments

Thanks to Mr YubingGuo and Chenhui Peng for useful discussion on droplet texture simulation.

Disclosure statement

No potential conflict of interest was reported by the authors.