Particle Scattering Factor of Janus Micelles

Abstract

We calculate scattering curves from Janus micelles based on a new particle scattering factor which we tested against Monte Carlo simulations. If we compare scattering data from Janus micelles with data of core−shell particles, we find that it is virtually impossible to distinguish the particle scattering factors of the two structures, if the scattering length densities of the respective segments are similar. As intuitively expected, this situation worsens if the particles have a finite spread of radii and/or scattering length densities. We show, however, that even in this case a positive identification of Janus micelles is possible on the basis of scattering experiments, if contrast variation techniques are applied. For this purpose the outer radius of the micelle should be larger than twice the inner radius, and the scattering length densities of the two Janus face segments should differ at least by a factor of 2. The most favorable conditions occur when the scattering length density of the core is the mean value of the two outer segments.