|133. Schubert, D.W.; Pannek, M.; Müller, A.H.E.: Novel map for polymer miscibility as revealed by neutron reflectometry, Physica B (Amsterdam) 276-278, 365 (2000)|
|Key words: Interfaces; Polymer films; Polymers; Reflectometry|
During annealing, above the glass transition temperatures the interface width between incompatible polymers increases with time, reaching an equilibrium value (typically 2 and 15 nm), which according to mean-field theory is determined by the Flory¯Huggins¯Stavermann interaction parameter . The quantity is a measure of polymer compatibility, although it is not well understood on a molecular basis and is often used as an empirical parameter. The purpose of this work is to reveal a correlation of chemical structure and the interaction parameter . A novel scheme is used for a graphical representation of this correlation. The interaction parameters are calculated consistently from interfacial width values and from the compositions of coexisting phases, accessible by neutron reflectometry. This is an important fact because interfaces might be enlarged due to capillary waves and would result in wrong values for the interaction parameter. A useful differential equation is presented connecting compositions of coexisting phases and interfacial profile.