title: Melt processing of hexa-peri-hexabenzocoronene on the water surface.
abstract: A discotic polycyclic aromatic hydrocarbon, hexa-peri-hexabenzocoronene, was oriented by slow cooling from the isotropic phase on a water surface as a film. For melt processing at low temperatures, an HBC derivative with long swallow-tailed alkyl side chains was chosen. The supramolecular organization in the resulting thin layer was investigated by electron microscopy. In high-resolution mode, the structural study showed large domains in which the columnar structures were oriented uniaxially with an edge-on arrangement of the hydrophobic molecules. The length of the stacks exceeded several hundred nanometers without obvious defects. The small-area analysis by TEM allowed the direct visualization of individual packed molecules. Electron diffraction revealed a high in-plane order of the columnar superstructures in which the discs were tilted by ca. 40° with respect to the stacking direction. This is the first example of a discotic system melt processed on the water surface yielding a pronounced order.
authors.affiliation: Max Planck Institute for Polymer Research, Mainz, Germany.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Pisula
authors.forename: Zeljko
authors.initials: Z
authors.lastname: Tomović
authors.forename: Ute
authors.initials: U
authors.lastname: Kolb
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen