Molecular Self-Assembly in Topological Defects of Liquid Crystals

Topological defects in liquid crystals (LCs) have been used to organize colloidal dispersions and template polymerizations, leading to a range of elastomers and gels with complex mechanical and optical properties. However, little is understood about molecular-level assembly processes within the cores of topological defects. This presentation will describe how nanoscopic environments defined by LC topological defects can selectively trigger processes of molecular self-assembly. By using fluorescence microscopy, cryogenic transmission electron microscopy and super-resolution optical microscopy, key signatures of molecular self-assembly of amphiphilic and polymeric molecules in topological defects are observed - including cooperativity, reversibility, and controlled growth of the molecular assemblies. By using polymerizable amphiphiles, we demonstrate preservation of molecular assemblies templated by defects, thus providing insights into the nanoscopic structure of the cores of topological defects. We also find that molecular self-assembly can select for and stabilize specific types of defects, leading to soft matter that is exquisitely responsive to the presence of particular classes of synthetic and biological lipids.