| The surface of a soft elastic film becomes unstable and forms self-organized patterns by merely bringing it in contact of a rigid flat surface. The resulting isotropic structures in the form of labyrinths, pillars and cavities have a characteristic wavelength, l ~ 3H, where H is the film thickness. The talk will focus on how ordered meso scale structures over large areas can be created by aligning, modulating, in situ tuning and miniaturizing theses random instability structures with simple strategies like variation in the film stamp separation distance, using a patterned contactor or a patterned substrate, use of an elastic bilayer. Many distinct complex structures, including 2 D ordered structures can be engineered from a simple stripe patterned stamp, offering the ability to engineer structures that are distinct from a positive or negative replica of the stamp. The elastic nature of the instability patterns allows in situ manipulation and reconfiguration of structures. The proposed technique is suitable for large area, rapid patterning of polymers for bulk-nano applications. |
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