DYNAMIC STRUCTURE FACTOR OF MICROEMULSIONS

The dynamic structure factor G(k, omega) is studied in a time-dependent Ginzburg-Landau model for microemulsions in thermal equilibrium by field-theoretic perturbation methods. For small viscosities, the structure factor develops a peak at a nonzero frequency omega, for fixed wavelengths of the order of the typical domain size of oil and water regions. This implies that the intermediate scattering function oscillates in time. We give a simple explanation for these temporal oscillations by considering the flow through a tube with a radius-dependent tension.