Mechanical confinement effects on the phase separation morphology of polymer blend thin films

We have measured the phase separation morphology of polystyrene–poly (methyl methacrylate) (PS-PMMA) blend films of thickness h on a silicon oxide (SiOx) substrate with a SiOx capping layer. We observe a novel phase separation morphology for small capping layer thicknesses L and a transition from lateral to lamellar morphology as L is increased. We present a simple model that explains the observed lateral morphology and the transition in …