title: Lyotropic hexagonal columnar liquid crystals of large colloidal gibbsite platelets.
abstract: We report the formation of hexagonal columnar liquid crystal phases in suspensions of large (570 nm diameter), sterically stabilized, colloidal gibbsite platelets in organic solvent. In thin cells these systems display strong iridescence originating from hexagonally arranged columns that are predominantly aligned perpendicularly to the cell walls. Small angle X-ray scattering and polarization microscopy indicate the presence of orientational fluctuations in the hexagonal columnar liquid crystal phase. The presence of decoupling of the average platelet orientation and the column axis as well as column undulations leading to a decrease of the effective column diameter are discussed. The fact that these phenomena are particularly pronounced in the vertical direction and are enhanced toward the bottom part of the system points to the role of gravitational compaction on the structure.
authors: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, The Netherlands. m.mourad@ucl.ac.uk
authors: Maurice C D
authors: MC
authors: Mourad
authors: Andrei V
authors: AV
authors: Petukhov
authors: Gert Jan
authors: GJ
authors: Vroege
authors: Henk N W
authors: HN
authors: Lekkerkerker
mesh_terms: D003102:Colloids / Q000138:chemical synthesis / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D003102:Colloids