Controllable formation of periodic wrinkles in Marangoni-driven self-assembled graphene film for sensitive strain detection

Controllable formation of microstructures in the assembled graphene film could tune the physical properties and broaden its applications in flexible electronics. Many efforts have been made to control the formation of wrinkles and ripples in graphene films. However, the formation of orderly wrinkles in graphene film remains a challenge. Here, we reported a simple strategy for the fabrication of graphene film with periodic and parallel wrinkles with a pre-stretched polydimethylsiloxane substrate. The width of the wrinkles in graphene can be controlled by changing the pre-stretched strain of the substrate. The average width of wrinkles in graphene film on the substrate with pre-stretched strain of 10%, 20%, and 50% was about 3.68, 2.99 and 2.01 µm, respectively. The morphological evolution of wrinkled double-layered graphene under mechanical deformation was observed and studied. Furthermore, a strain sensor was constructed based on the wrinkled graphene, showing high sensitivity, large working range and excellent cyclic stability. These strain sensors show great potential in real-time motion detection, health surveillance and electronic skins.