Lithographically induced self-assembly of periodic polymer micropillar arrays

We observed, and believe it to be the first time, the self-formation of periodic, supramolecular (micrometer scale) pillar arrays in a thin, single-homopolymer film melt, which was originally fiat on a plate. The self-formation was induced by placing a second plate (called a mask) a distance above the polymer film. The pillars, formed by rising against the gravitational force and surface tension, bridge the two plates. The pillar height is equal to the plate-mask separation, which is two to seven times the film's initial thickness. If the surface of the mask has a protruding pattern (e.g., a triangle or rectangle), the pillar array can be formed only-under the protruding pattern with the edge of the array aligned to the boundary of the mask pattern. We also discuss a model and novel applications of lithographically induced self-assembly.