Bending elasticity of the surfactant monolayer in droplet microemulsions: Determination by a combination of dynamic light scattering and neutron spin-echo spectroscopy

The bending elastic energy of a surfactant monolayer at the oil-water interface in a microemulsion system can be described by the spontaneous monolayer curvature and two elastic constants $\kappa$ and $\overline{\kappa }$. Here we present the determination of these constants by a combination of dynamic light scattering and neutron spin-echo spectroscopy for the octane-${\mathrm{C}}_{10}{\mathrm{E}}_5$-water microemulsion on the water continuous side of the phase diagram. Small-angle neutron scattering data are also presented and compared to the light scattering results.