On a discussion about the determination of surface characteristics of microemulsion droplets from static and dynamic scattering experiments

The interpretation of static and dynamic scattering experiments on droplet microemulsions is discussed. We review the arguments given in our previous papers that call into question the methods of current determination of basic phenomenological characteristics of the droplet surfactant monolayer, such as the bending and Gaussian rigidities. We give also responses to our criticism by T. Hellweg, B. Farago, M. Gradzielski, D. Langevin, and S. Safran (Colloids and Surfaces A 221 (2003) 257 and some other works by these authors). They agree with some of our objections; the rest of their response is shown to be flawed. We also show that in many points their way of discussion is improper and misleading. It is concluded that the values of the parameters of microemulsion droplets, as extracted in their experiments, are not reliable and should be reexamined.