Coupling of wrinkle patterns to lithographic patterns

Spontaneously formed microwrinkle patterns on a metal-capped elastomer surface are modulated by introducing lithographic structures on the original surface as spatial triggers for directed wrinkle formation. The lithographic patterns are fabricated by utilizing an array of microspheres or a thin polymer film with hexagonally-packed micro pores as a lithographic mask. When the lateral periodicity of the lithographic pattern is close to the wavelength of wrinkles, a novel directional order originating from the hexagonal packing of microspheres is induced. Otherwise, the wrinkle crests tend to form along the small ridges of the lithographic structure. The compression direction-dependent and reversible ordering of wrinkle patterns by compressive strain is also found for patterns with directional order.