https://doi.org/10.1140/epje/i2010-10668-1
Regular Article
Dynamics of the interfacial film in bicontinuous microemulsions based on a partly ionic surfactant mixture: A neutron spin-echo study
1
Soft Matter und Funktionale Materialien, Helmholtz-Center Berlin for Energy and Materials, 14109, Berlin, Germany
2
Armed Forces Scientific Institute for NBC-Protection, 29633, Munster, Germany
3
Laboratoire Léon Brillouin, C.E.A.-C.E.N. Saclay, 91191, Gif-sur-Yvette Cedex, France
4
Institute Laue Langevin, POB 156X, 38042, Grenoble, France
5
Physikalische und Biophysikalische Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
* e-mail: thomas.hellweg@uni-bielefeld.de
Received:
5
March
2010
Revised:
3
August
2010
Accepted:
12
October
2010
Published online:
9
November
2010
In a microemulsion system based on a mixture of nonionic and ionic surfactants the addition of alcohol instead of changing the temperature was used to tune the curvature of the surfactant interface. The influence of the addition of the short-chain alcohol 2-propanol in the system water-perchloroethylene-Marlowet IHF-2-propanol is studied using neutron spin-echo spectroscopy. In contrast to alcohols with long alkyl chains 2-propanol is no strong co-surfactant, but changes the properties of the solvents. The present contribution focuses on the bicontinuous phase in this system and a quantitative analysis of the obtained neutron spin-echo data is proposed within the theoretical framework given by Zilman and Granek for amphiphilic membranes. It turns out that, in addition to the local movements of the surfactant film, also a collective diffusional mode of the bicontinuous structure has to be taken into account. The presented approach allows to calculate the bending elastic constant 
of the film. The approach is subsequently applied to follow changes of as induced by changes of the alcohol concentration.
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2010
