Fig. 1From: Wearable piezoresistive strain sensor based on graphene-coated three-dimensional micro-porous PDMS spongePhotos of a cube sugar, b bare PDMS sponge, and c graphene-coated PDMS sponge. d–i Show the SEM images of surface of cube sugar, bare PDMS sponge, and graphene-coated PDMS sponge, respectivelyBack to article page