Nanoscale crystalline order in lyotropic solution of supramolecular hollow cylinders

Nanoscale 3D order is observed in the lyotropic columnar phase of supra-molecular aggregates by ionic planar oligomers. The meso-scopic structure and dynamics of the supramolecular LLC are characterized by polarized optical microscope, Cryo-TEM and X-ray scattering experiments. We observe the formation of tubular aggregates or columns with diameter about 15 nms of which the morphology remains almost unchanged with concentration. The columns are further bundled into hexagonal columnar phase which swells with decreasing concentration. Fiber diffraction on concentrated solutions display Bragg reflection arcs, indicating 3D crystalline order at nanometer scale and interlock between the columns. As concentration drops, the reflection arcs gradually fade but remain visible even at surface to surface separation about 8nm, suggesting effective inter-column correlation across rather long distances. Concomitant weakening of intra-column order upon dilution is evident in the dynamics of the supramolecular columns probed by X-ray Photon Correlation Spectroscopy. The 3D order in the supramolecular solutions is analogous to ordered column phase of thermotropic liquid crystals. The results and underlying mechanism are compared to semi-crystalline phase of covalently bonded DNAs.