Segregation in epoxy/amine systems on iron oxide surfaces†

Segregation of epoxy/amine precursors at solid interfaces can have important consequences in the formation of thin, epoxy–amine films. In this work we study the segregation of a model epoxy molecule (DGEBA) and an amine (MXDA) on different iron oxide surfaces. We found that the extent of segregation can depend on the nature of the solid surface, and that segregation on goethite surfaces is more pronounced than on hematite and magnetite, regardless of the composition of the film. Detailed analysis of the interface shows that the contact layer is not well mixed and regions rich in amine and rich in epoxy molecules can be identified. Furthermore, we suggest that the larger segregation observed in goethite is a consequence of the way the molecules pack on the surface, with stricter binding sites observed at the goethite surface.