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| Hauptseite > Publikationsdatenbank > Capillary condensation in microemulsions |
| Hauptseite > Publikationsdatenbank > Capillary condensation in microemulsions |
| Poster (Outreach) | FZJ-2020-00165 |
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2019
Abstract: Microemulsions are thermodynamically stable mixtures of oil and water that are mediated by the surfactant. Locally, there are oil and water domains that are observable by scattering experiments that are separated by the surfactant film. The domain sizes are usually a few nanometers and display shapes from spherical droplets over elongated droplets to the bicontinuous sponge phase. In the following we restrict ourselves to the bicontinuous microemulsion. When exposing the microemulsion to hydrophilic surfaces, a lamellar order is locally induced next to the interface. From spectroscopic measurements, we know that the membrane fluctuations in microemulsions are faster in the lamellar state. This is connected to the lubrication effect, because the lamellae can slide off easier and the motions are faster. In spectroscopic measurements with hydrophilic clay particles, we could show, that the platelet diameter causes a cutoff of the undulation modes, and larger platelets cause a better order with longer wavelength modes. The capillary condensation in bicontinuous microemulsions is expected to take place when two parallel surfaces are narrowed that result in a completely lamellar microemulsion (Figure). So far, all experiments stayed at relatively low clay concentrations, when the system is still liquid. The lamellar fraction in microemulsions with 1% clay is around 25% in volume. We now tried to observe the capillary condensation with increasing clay concentration using small angle neutron scattering (SANS) and neutron spin echo (NSE) spectroscopy.
Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Soft Condensed Matter (2nd)
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