Multimodal Wrinkle Micro-Nanoarchitectonics by Patterned Surface Material Properties for Transformative Structural Coloration

When an external stimulus is used to generate nanoscale wrinkles on the ductile top surface of a multilayered substrate, the geometrical and optical features are known to be controlled by the material and structural properties of the laminated film. Herein, a thin tri-layer film is fabricated that can generate various wrinkles on transparent and flexible films in the presence of external mechanical bending. In particular, the wavelength of the wrinkles is shown to be controllable on the tens of nanometers scale by modulating the material properties of each layer. This active modulation plays a critical role in determining the resulting structural color spectra. In other words, the wrinkles function as a diffraction grating so that the film displays bright structural colors under bending conditions. After the bending stress is released, the wrinkles disappear, and the film returns to its transparent state. Finally, the remarkable potential of the material and structural patterning technique is demonstrated for structural coloration applications such as multimodal displays and novel barcode-based anti-counterfeiting.