A SMALL-ANGLE NEUTRON-SCATTERING STUDY OF DENSITY-FLUCTUATIONS AT NEAR-CRITICAL REGION AND A VAN-DER-WAALS MODEL IN A 3-COMPONENT MICROEMULSION

A small angle neutron scattering investigation near the critical point of D2O/n-decane/AOT water-in-oil microemulsion was carried out. Altho ugh the previous results in literature indicated the Ising behavior, t he meanfield behavior for the susceptibility was observed. From the an alysis of the susceptibility divergence, binodal point and spinodal po int for each composition were given. In order to explain these points, the Gibbs free energy of mixing with the Flory-Huggins interaction pa rameter is introduced in the framework of the van der Waals model.