This article reviews non-linear macroscopic pattern formation on polymer film surfaces. As a result of solvent evaporation from a dilute polymer solution heated from below, the free surface of the as-cast polymer film undulates and exhibits a two-dimensional pattern due to the undulation. For an ordinary polymer, a hexagonal (or polygonal) pattern was obtained. This pattern, due to surface undulation, was found to be ascribed to convection existing in the solution. On the other hand, a very peculiar concentric-ring pattern was observed for an SBS film, where SBS designates polystyrene-
block-polybutadiene-
block-polystyrene triblock copolymers. Note that this sample forms lamellar microdomain structures with a ca. 22 nm identity period. In this pattern, a set of concentric rings contained in a cellular compartment is a unit constituent and was found to be a set of wrinkles on the surface. The mechanism of formation of the concentricring pattern is presented in this article, and moreover, control of the morphology of the pattern is discussed.
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