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RESEARCH PRODUCT
Melt processing of hexa-peri-hexabenzocoronene on the water surface
Klaus MüllenUte KolbWojciech PisulaZeljko Tomovicsubject
chemistry.chemical_classificationDiscotic liquid crystalStacking02 engineering and technologySurfaces and Interfaces010402 general chemistry021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciences0104 chemical sciencesCrystallographyElectron diffractionchemistryTransmission electron microscopyPhase (matter)ElectrochemistrySide chainGeneral Materials Science0210 nano-technologyColumnar phaseSpectroscopyAlkyldescription
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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-02-15 |