(662a)  Molecular Self-Assembly in Liquid Crystals

Topological defects present in liquid crystals (LCs) have been widely used to organize colloidal dispersions and template polymerizations, leading to a range of assemblies, elastomers and gels with complex mechanical and optical properties. However, little is understood about molecular-level assembly processes within defects, although within the nanoscopic cores of singular topological defects the ordering of mesogens is known to be diminished relative to the bulk LC. This presentation will report that 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 molecules in topological defects are observed - including cooperativity, reversibility, and controlled growth of the molecular assemblies. By using amphiphiles that can be photocrosslinked, we also demonstrate preservation of molecular assemblies templated by defects, including nanoscopic â??o-ringsâ? synthesized from â??Saturn-ringâ? disclinations. Our results reveal that topological defects in LCs are a versatile class of three-dimensional, dynamic and reconfigurable templates that can direct processes of molecular self-assembly in a manner that is strongly analogous to other classes of macromolecular templates (e.g., polymerâ??surfactant complexes).