In the system AOT-isooctane-water, the reverse micelle radii, governed by the water content, vary upon addition of small amounts of compounds solubilized in the microemulsion. These small variations were measured by high-resolution small-angle X-ray scattering. Structural changes are related to the solubilization sites by means of simple geometrical models. Solutes situated at the interface decrease the water core radius; solutes located in the water core increase this radius.
Source : Solubilization by reverse micelles: solute localization and structure perturbation.
M.P. Pileni, T. Zemb and C. Petit Chem. Phys. Letters., 1985, 118, 414.