title: Dynamics and kinetics of structure formation in molecularly tethered fluorocarbon/hydrocarbon amphiphiles.
abstract: Biphasic fluorocarbon/hydrocarbon amphiphiles tethered to cores at distances commensurate with their packing requirement can provide thermodynamic pathways toward equilibrium. This contrasts with the analogous semifluorinated alkanes. The dynamics of a fluorous biphasic hexa(3,5-substituted-phenyl)benzene (HPB) is studied with dielectric spectroscopy as a function of temperature and pressure in comparison to the parent biphasic diphenylacetylene (DPA). Dielectric spectroscopy is a sensitive probe of the fluorocarbon environment through the end C-F dipole. Four dielectrically active processes were observed that associate with the CF(3) environment within the different phases (isotropic, liquid-like lamellar, solid lamellar, glassy state). Pressure facilitates the construction of the equilibrium phase diagram. The kinetic pathways to fluorocarbon organization are explored by pressure-jump experiments. A highly cooperative process was found that is atypical of a nucleation and growth process expected for first-order transitions.
authors.affiliation: Department of Physics, University of Ioannina, GR-45110, Ioannina and Foundation for Research and Technology-Biomedical Research Institute, Ioannina, Greece.
authors.forename: M M
authors.initials: MM
authors.lastname: Elmahdy
authors.forename: C G
authors.initials: CG
authors.lastname: Clark
authors.forename: H-J
authors.initials: HJ
authors.lastname: Butt
authors.forename: K
authors.initials: K
authors.lastname: Müllen
authors.forename: G
authors.initials: G
authors.lastname: Floudas