Fabrication of composite structures based on microwrinkles

Abstract

The composite structures were fabricated by wrinkle formation and optical lithography. Complex and ordered wrinkle patterns are spontaneously created on metal thin films thermally deposited onto elastomeric polymers owing to mismatch of thermal expansion. In the experiments, a thin film of Au with 20-50 nm thick was deposited by ion sputtering on the surface of polydimethylsiloxane (PDMS) substrates. To modulate wrinkle patterns regularly and uniformly, optical lithography was used to fabricate given structures in Silicon wafers, and these structures were transferred onto PDMS substrates by replica molding. In the process of wrinkle formation, the configuration on the PDMS substrates could effect or regulate wrinkle formation, and so the composite structures effectively integrate the lithographic and wrinkle patterns. These unique structures have potential application in optical devices, sensors and actuators.