Bare-core approximation: a useful approach to SAS data of block copolymer micelles

A middle part of small-angle scattering curves of block copolymer micelles can frequently be described satisfactorily by the scattering function of homogeneous spherical particles (bare-core approximation). This makes it possible to easily determine structure characteristics (mean radius, polydispersity, volume, mass) of the micelle core. Thus, information about the internal structure of the core/corona micellar particles can be obtained without using co-polymers with labelled blocks. Though not universal, this approach is applicable to numerous micellar systems including those formed by hydrogenous copolymers in deuterated solvents. The approach can be also used if the relative excess scattering amplitudes of the core and corona are not a priori known, e.g., in studies of solubilization phenomenon.