Self-assembled nested wrinkling patterns with pre-stretched polymer substrates

The surface modulation of thin films has potential application in microelectromechanical and nanoelectromechanical structures. Patterns comprising nested self-similar wrinkling patterns were obtained under dewetting of polymethyl methacrylate (PMMA) acetone solution deposited on the pre-stretched polydimethylsiloxane (PDMS) elastomer substrates. SEM of these samples indicated that the individual wrinkle generations are arranged in nested patterns, where each larger wrinkle resides underneath and represents a scaledup version of the smaller wrinkle. Such skins may be important, for example, in robotics applications in which spatially resolved touch sensitivity is required, or for smart materials that can sense shape changes with high-resolution.