Investigation of the interface between polymers: a comparison of scattering and reflectivity techniques

With the techniques of small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) the interfacial region between polymers forming a two-phase structure can be investigated. Various approaches are possible including the classical Porod analysis as well as the Fourier transform, sandwich or contrast-matching techniques. Their application for the determination of the interface width and profile between polymer phases is discussed. As an alternative method X-ray and neutron reflectometry from polymer layer systems has recently been introduced. It allows an accurate determination of various interfacial parameters provided a flat and smooth interface with sufficient contrast between the materials can be prepared. The techniques are compared and discussed with respect to the information which is obtained on the interfacial region of polymers.