SMALL-ANGLE NEUTRON-SCATTERING FROM DIFFUSE INTERFACES .2. POLYDISPERSE SHELLS IN WATER-N-ALKANE-C(10)E(4) MICROEMULSIONS

A new model for the shell structure of surfactants in droplet microemu lsions is described in which the scattering length density distributio n of the interface is treated as a Gaussian profile. The corresponding particle form factor and scattering intensity on an absolute scale ar e derived in analytical form for the case of both monodisperse and pol ydisperse droplets. It is compared with the more conventional model of concentric shells with sharp boundaries. We find that both models dif fer mainly in their high-q behavior. We use both models to describe ex perimental SANS spectra of droplet microemulsions in shell contrast. T he new model proves to provide a more accurate description of the expe rimental data.