Inspired by origami, the ancient art of paper folding, Chinese researchers have created pre-programmed graphene-based paper that can self-fold into boxes, hand-like grippers, and even walking devices [Mu et al., Sci. Adv. (2015) 1, e1500533].
Folding and cutting two-dimensional materials is attracting new interest from materials scientists as an easy way of creating intricate three-dimensional structures. Graphene, with its exceptional strength, flexibility, electronic properties, and chemical stability, is the ultimate soft but strong two-dimensional material.
"We used chemically converted graphene nanosheets as nanoscale building blocks to fabricate self-folding graphene paper," explains Hongzhi Wang of Donghua University, who led the research along with Qinghong Zhang. "Our graphene film is almost as thin and flexible as a sheet of paper."
The team cut out various shapes from a graphene-based paper that, when exposed to gentle light or heat, self-fold into three-dimensional shapes. The self-folding behavior can be programmed so that devices fold and unfold repeatedly to mimic walking and can even be prompted to turn corners.