Wipf, R. ; Kraska, M. ; Spehr, T. ; Nieberle, J. ; Frey, H. ; Stühn, B. (2011)
Interaction between a water-in-oil microemulsion and a linear-dendritic poly(propylene oxide)–polyglycerol block copolymer.
In: Soft Matter, 7 (22)
doi: 10.1039/C1SM06066J
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
We present small angle scattering and dielectric spectroscopy results on the influence of an amphiphilic diblock copolymer on the structure and dynamics of a microemulsion. We use a water-in-oil (w/o) droplet microemulsion based on the anionic surfactant AOT (sodium bis(2-ethylhexyl) sulfosuccinate), that forms spherical water droplets coated by a monolayer of AOT dispersed in the continuous oil matrix. The studied polymer consists of a hydrophobic poly(propylene oxide) (PPO) block and a hydrophilic hyperbranched polyglycerol with 74 glycerol units (NG74). Combining small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) we find that the droplet structure is preserved upon addition of PPO-NG74 while the interaction distance between droplets increases with increasing polymer content. From SANS we deduce that the NG74 block is located inside the droplets while the PPO extends into the oil matrix. By measuring the dc-conductivity as a function of temperature we study the dynamic percolation of the microemulsion. While the static structure of the droplet phase remains unchanged, both percolation temperature and phase separation temperature increase linearly with increasing polymer concentration. We explain this finding by a stiffening of the AOT layer induced by the polymer. By means of dielectric spectroscopy we observe two relaxations. The slower one can be related to a polarization at the interface of the water core and the AOT shell (core relaxation) and the faster one is due to the ions in the AOT-shell (cluster relaxation). Polymer addition is found to have a significant influence only on the core relaxation. We apply the cluster relaxation model to estimate the cluster size evolution with increasing polymer concentration.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2011 |
| Autor(en): | Wipf, R. ; Kraska, M. ; Spehr, T. ; Nieberle, J. ; Frey, H. ; Stühn, B. |
| Art des Eintrags: | Bibliographie |
| Titel: | Interaction between a water-in-oil microemulsion and a linear-dendritic poly(propylene oxide)–polyglycerol block copolymer |
| Sprache: | Englisch |
| Publikationsjahr: | 6 Oktober 2011 |
| Verlag: | The Royal Society of Chemistry |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Soft Matter |
| Jahrgang/Volume einer Zeitschrift: | 7 |
| (Heft-)Nummer: | 22 |
| DOI: | 10.1039/C1SM06066J |
| Zugehörige Links: | |
| Kurzbeschreibung (Abstract): | We present small angle scattering and dielectric spectroscopy results on the influence of an amphiphilic diblock copolymer on the structure and dynamics of a microemulsion. We use a water-in-oil (w/o) droplet microemulsion based on the anionic surfactant AOT (sodium bis(2-ethylhexyl) sulfosuccinate), that forms spherical water droplets coated by a monolayer of AOT dispersed in the continuous oil matrix. The studied polymer consists of a hydrophobic poly(propylene oxide) (PPO) block and a hydrophilic hyperbranched polyglycerol with 74 glycerol units (NG74). Combining small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) we find that the droplet structure is preserved upon addition of PPO-NG74 while the interaction distance between droplets increases with increasing polymer content. From SANS we deduce that the NG74 block is located inside the droplets while the PPO extends into the oil matrix. By measuring the dc-conductivity as a function of temperature we study the dynamic percolation of the microemulsion. While the static structure of the droplet phase remains unchanged, both percolation temperature and phase separation temperature increase linearly with increasing polymer concentration. We explain this finding by a stiffening of the AOT layer induced by the polymer. By means of dielectric spectroscopy we observe two relaxations. The slower one can be related to a polarization at the interface of the water core and the AOT shell (core relaxation) and the faster one is due to the ions in the AOT-shell (cluster relaxation). Polymer addition is found to have a significant influence only on the core relaxation. We apply the cluster relaxation model to estimate the cluster size evolution with increasing polymer concentration. |
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik > Institut für Festkörperphysik (2021 umbenannt in Institut für Physik Kondensierter Materie (IPKM)) > Experimentelle Physik kondensierter Materie 05 Fachbereich Physik > Institut für Festkörperphysik (2021 umbenannt in Institut für Physik Kondensierter Materie (IPKM)) 05 Fachbereich Physik |
| Hinterlegungsdatum: | 11 Apr 2012 06:53 |
| Letzte Änderung: | 05 Mär 2013 10:00 |
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