1. Self-Assembly, Molecular Dynamics, and Kinetics of Structure Formation in Dipole-Functionalized Discotic Liquid Crystals.
- Author
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Elmahdy, Mahdy M., Xi Dou, Mondeshki, Mihail, Floudas, George, Butt, Hans-Jüurgen, Spiess, Hans W., and Müllen, Klaus
- Subjects
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MOLECULAR dynamics , *LIQUID crystals , *MAGNETIC dipoles , *CRYSTALS , *THERMODYNAMICS - Abstract
The self-assembly, the molecular dynamics, and the kinetics of structure formation are studied in dipole-functionalized hexabenzocoronene (HBC) derivatives. Dipole substitution destabilizes the columnar crystalline phase except for the dimethoxy- and monoethynyl-substituted HBCs that undergo a reversible transformation to the crystalline phase. The disk dynamics are studied by dielectric spectroscopy and site- specific NMR techniques that provide both the time-scale and geometry of motion. Application of pressure results in the thermodynamic phase diagram that shows increasing stability of the crystalline phase at elevated pressures. Long-lived metastability was found during the transformation between the two phases. These results suggest new thermodynamic and kinetic pathways that favor the phase with the highest charge carrier mobility. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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