Dresden 2011 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: Poster: Colloids and Complex Liquids
CPP 38.19: Poster
Wednesday, March 16, 2011, 17:00–19:00, P2
Diffusion of amphiphiles and proteins in the bicontinuous phase of a microemulsion: A fluorescence correlation spectroscopy study — •Ralph Neubauer1, Sebastian Höhn1, Christoph Schulreich1, and Thomas Hellweg2 — 1Physikalische Chemie I, Universität Bayreuth, Deutschland — 2Physikalische und Biophysikalische Chemie (PC III), Universität Bielefeld, Deutschland
The bicontinuous phase in a microemulsion is often characterized by dynamic light scattering (DLS) or small angle neutron scattering (SANS).
Here we analyze the diffusion of a bicontinuous phase by fluorescence correlation spectroscopy (FCS) to determine the diffusion time and coefficient of tracer particles. FCS is a powerful technique for obtaining readings and results much faster
than in an DLS experiment.
In the present work fluorescein labeled amphiphilic molecules are inserted in the microemulsion. By measuring the diffusion of the amphiphiles, the “breathing movement” of the interface layer can be identified. Furthermore, the movement of fluorescent labeled proteins in the water domain is detected and the confinement effect can be identified.
Moreover we compare results from different DLS, SANS and FCS measurements for the bicontinuous phase of sugar surfactant based microemulsions. We also show conclusions for model systems and corresponding systems with technical-grade surfactants. The challenge especially for technical-grade systems is the fluorescence of impurities in the surfactants all over the visible range which cannot be extinguished.