Dynamics in an oil-continuous droplet microemulsion as seen by quasielastic scattering techniques

This contribution presents the direct determination of the bending elasticity of the surfactant film in an oil-continuous microemulsion by means of neutron spin-echo spectroscopy and dynamic light scattering. The investigated system is C(10)E(4)/water dispersed in n-octane. The values obtained for the bending elastic constants are compared to results from indirect determinations based on the spinning drop method. While good agreement is found for kappa, the values computed for k differ slightly when the calculation is based on polydispersities obtained from small angle neutron scattering experiments. Better agreement is reached using the polydispersities calculated from dynamic light scattering data. Furthermore, problems which seem to be specific for oil-continuous systems are addressed.