Experimental Insights into the Nanostructure of the Cores of Topological Defects in Liquid Crystals.

Abstract

The nanoscopic structure of the cores of topological defects in anisotropic condensed matter is an unresolved issue, although a number of theoretical predictions have been reported. In the experimental study reported in this Letter, we template the assembly of amphiphilic molecules from the cores of defects in liquid crystals and thereby provide the first experimental evidence that the cores of singular defects that appear optically to be points (with strength m=+1) are nanometer-sized closed-loop, disclination lines. We also analyze this result in the context of a model that describes the influence of amphiphilic assemblies on the free energy and stability of the defects. Overall, our experimental results and theoretical predictions reveal that the cores of defects with opposite strengths (e.g., m=+1 vs m=-1) differ in ways that profoundly influence processes of molecular self-assembly.