Clustering and relaxation in oil-continuous microemulsions

In the droplet phase of oil-continuous microemulsions, clustering of the droplets has been observed by a number of experimental techniques such as dielectric constant and viscosity measurements. The clustering is found to be characterized by a droplet radius dependent binding enthalpy. Structure factors obtained using SAXS are found to fit those predicted by Baxter's sticky hard sphere model. An extension of this model to a positive value of the binding enthalpy is given. In dynamic Kerr measurements the slow relaxation due to rotation of clusters is observed.