ABSTRACT
Interfacial properties between immiscible polymers, e.g., interfacial thickness and interfacial tension, are related to polymer–polymer miscibility. Generally, the lower critical solution temperature behavior is explained by the free volume effect based on the equation of state theories of polymer mixtures. The polymer–polymer interactions of immiscible mixtures on the basis of interfacial thickness measured by ellipsometry were estimated. Systematic investigations between the miscibility and interfacial behavior in polymer–polymer mixtures are necessary. Ellipsometry is a powerful tool for measuring the interfacial thickness in polymer–polymer mixtures. These measurements can be carried out for immiscible polymer blends as well as miscible blends. The miscibility window behavior has been reported for many blends, e.g., poly(methyl methacrylate) and styrene-acrylonitrile random copolymer. In random copolymers a different mechanism causing miscibility becomes effective without specific interaction. The thin films were prepared by spin-coating the polymer solutions onto a silicon wafer and floating off the resulting films onto a water surface.
