Creation and topological charge switching of defect loops on a long fibre in the nematic liquid crystal

ABSTRACT

We demonstrate new type of topological defects on a homeotropic fibre aligned perpendicular to the nematic director in a planar nematic cell. Contrary to expectations we can create defect loops which are encircling the fibre along its short axis and are strongly tilted with respect to the fibre. Such loops are always accompanied by two topological solitons, which emanate from the loop and propagate to the left- and right-hand side of the fibre. Unlike previously reported closed loops of either positive and negative charge, encircling the fibre parallel to the nematic director, these loops can carry either positive or negative charge, or can be charge neutral and very stable. We show how to switch the charge of individual loops from positive to neutral and negative charge by adding unit monopoles of appropriate topological charge. We demonstrate new type of interaction of dipolar colloids with these new topological entities on a fibre.

Graphical Abstract

KEYWORDS:

• Microconfined liquid crystals
• topological defect
• homeotropic fibre
• colloidal interaction
• entanglement
• anchoring
• liquid-solid interfaces

Acknowledgments

This work was supported by the University of Leeds (M. N.) and the Slovenian Research Agency (ARRS) contract P1–0099 (I. M.).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the University of Leeds (M. N.); the Slovenian Research Agency (ARRS) contract [P1–0099] (I. M.).