Dynamics and Kinetics of Structure Formation in Molecularly Tethered Fluorocarbon/Hydrocarbon Amphiphiles
| Autor: | Mahdy M. Elmahdy, George Floudas, Klaus Müllen, Christopher G. Clark, Hans-Jürgen Butt |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
chemistry.chemical_classification
Chemistry Kinetics Nucleation Surfaces Coatings and Films Dielectric spectroscopy chemistry.chemical_compound Hydrocarbon Chemical physics Amphiphile Materials Chemistry Organic chemistry Lamellar structure Fluorocarbon Physical and Theoretical Chemistry Diphenylacetylene |
| Zdroj: | The Journal of Physical Chemistry B. 116:13812-13820 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp309465z |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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