Measuring bending rigidity and spatial renormalization in bicontinuous microemulsions

We demonstrate a new approach to determine the bending rigidity of the amphiphile film in microemulsions and sponge phases from neutron scattering data. This method is precise enough to measure the logarithmic scale dependence of the bending rigidity and its universal prefactor for the first time. Furthermore, we show that in the mushroom regime the bending rigidity of a membrane decorated by amphiphilic block copolymers increases linearly with the polymer concentration on the membrane; the amplitude is found to be about a factor 1.5 larger than theoretical results for ideal chains.