Domain Orientation and Grain Coarsening in Cylinder-Forming Poly(styrene-b-methyl methacrylate) Films

The domain orientation and grain sizes in cylinder-forming poly(styrene-b-methyl methacrylate) (PS-b-PMMA) films were systematically investigated as a function of film thickness (32–640 nm), annealing temperature (190–230 °C), and wetting behavior of PS-b-PMMA on substrates. The domain orientation at the film surface depended on film thickness as well as both the polymer–substrate and polymer−free surface boundary conditions. In thin films (thickness L 6L0, the two boundary conditions decoupled, and the polymer-free surface interaction determined the domain orientation of cylinders near the film surface regardless of the chemistry of the underlying substrate. The orientational...