(77a) Self-Organized Large Area Patterning of Soft Solids by Elastic Contact Lithography

The surface of a soft elastic film becomes unstable and forms self-organized patterns by merely bringing it in contact with a rigid flat plate. These isotropic structures in the form of labyrinths, pillars and cavities have a characteristic wavelength, L ~ 3H, where H is the film thickness (Phys. Rev. Lett. 85, 4329, 2000; Phys. Rev. Lett. 86, 119, 2001; Phys. Rev. Lett. 93, 018302, 2004). The elastic contact induced patterns can be ordered, aligned and modulated by varying the separation distance, using a patterned stamp or by a simple shear movement of the stamp. Many distinct complex structures are generated from a single simple 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 such as in micro-well arrays, optical coatings, structural colors, super-wetting, micro-batteries and smart adhesives.