Bi-defects of Nematic Surfactant Bilayers

TL;DR

This paper explores how topological defects in nematic bilayers induce coupled textures across monolayers, revealing the existence of bi-defects that influence the bilayer's structure and could be observed experimentally.

Contribution

It introduces the concept of bi-defects in nematic bilayers, showing their formation due to coupling and their characteristic wall structures, advancing understanding of defect interactions.

Findings

Topological defects on one monolayer induce textures on both layers.

Bi-defects are associated pairs of defects across layers.

Bi-defects create wall structures with distinct interior and exterior textures.

Abstract

We consider the effects of the coupling between the orientational order of the two monolayers in flat nematic bilayers. We show that the presence of a topological defect on one bilayer generates a nontrivial orientational texture on both monolayers. Therefore, one cannot consider isolated defects on one monolayer, but rather associated pairs of defects on either monolayer, which we call bi-defects. Bi-defects generally produce walls, such that the textures of the two monolayers are identical outside the walls, and different in their interior. We suggest some experimental conditions in which these structures could be observed.