title: Self-assembly, molecular dynamics, and kinetics of structure formation in dipole-functionalized discotic liquid crystals.
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.
authors.affiliation: Department of Physics, University of Ioannina, 451 10 Ioannina, Greece.
authors.forename: Mahdy M
authors.initials: MM
authors.lastname: Elmahdy
authors.forename: Xi
authors.initials: X
authors.lastname: Dou
authors.forename: Mihail
authors.initials: M
authors.lastname: Mondeshki
authors.forename: George
authors.initials: G
authors.lastname: Floudas
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Butt
authors.forename: Hans W
authors.initials: HW
authors.lastname: Spiess
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen