A geometric theory of wrinkling for confined shells: Part 3

Materials engineered through surface patterning are used for a broad array of applications, including flexible electronic and microfluidic devices, electronic skin, and many others. Microfabrication techniques based on elastic instabilities have attracted much attention because of their relative simplicity and potential for technological innovation. We employ Gaussian curvature as a mechanism for pattern formation: when a shallow curved shell is placed upon a liquid surface, well-defined domains of unidirectional wrinkles are formed. In the third part of this series of talks, we use finite element simulations and a theoretical approach based on the minimization of the elastic energy, to probe how the global arrangement of the patterns and wrinkling amplitude depends on the shape and curvature of the shell. We finally consider cases of shells with highly non-trivial boundary geometries and we demonstrate how this setup can be employed to harness surface structures with complex, yet predictable and controllable, topography. (This is part 3 in a 3-talk series).