Scalable optical manufacture of dynamic structural colour in stretchable materials.

Structurally coloured materials that change their colour in response to mechanical stimuli are uniquely suited for optical sensing and visual communication 1-4 . The main barrier to their widespread adoption is a lack of manufacturing techniques that offer spatial control of the materials' nanoscale structures across macroscale areas. Here, by adapting Lippmann photography 5 , we report an approach for producing large-area, structurally coloured sheets with a rich and easily controlled design space of colour patterns, spectral properties, angular scattering characteristics and responses to mechanical stimuli. Relying on just a digital projector and commercially available photosensitive elastomers, our approach is fast, scalable, affordable and relevant for a wide range of manufacturing settings. We also demonstrate prototypes for mechanosensitive healthcare materials and colorimetric strain and stress sensing for human-computer interaction and robotics.