Controlled wrinkle formation via bubble inflation strain engineering

We demonstrate herein a novel strategy that combines both strain engineering and geometrical confinement in one system to realize controlled wrinkling. The location, shape and size of air bubbles entrapped in poly(dimethylsiloxane) (PDMS) devices are precisely controlled via a soft lithography technique. During the Au sputtering process, thin PDMS covers are first stretched due to the bubble inflation under negative pressure. The subsequent Au coating results in Au–PDMS bilayer structure. When returned to atmospheric pressure, wrinkles form on the Au–PDMS bilayer. Furthermore, rational design for more complicated wrinkle patterns is possible with the initial development of strain analysis. We believe this strategy could be applicable to a large range of materials and would find applications in flexible electronics and optics design.