“Smart GO/RGO paper may find broad applications in intelligent devices,” Sun said. “In response to moisture, the anisotropic water adsorption causes it to curl in seconds.” The team has adapted the technology into robots that instantly morph from flat paper strips into inchworm-like crawlers that scoot across a surface, as into more complex autonomous claws that grasp and release tiny objects. Bilayers of RGO and GO react differently when approached with moisture, for example, an engineer’s sweaty finger, he said. Therefore, one side of the GO paper can be fully reduced due to the UV radiation-induced photochemical reactions, and the other side can survive as pristine GO.” This effect significantly alters the reduced graphene oxide (RGO) surface’s water-repelling capacity. “We recently found that focused sunlight can reduce GO paper to some extent. Sun, the director of JU’s Center for Ultrafast Optoelectronic Technologies, said his team’s ‘bots begin with graphene oxide (GO) paper exposed to UV radiation from sunlight.
#Walking papers series#
“Graphene has exhibited a series of enticing physical/chemical properties such as high electrical conductivity, transparency, biocompatibility, mechanical flexibility, strength, and good stability,” Sun said, distinguishing graphene and related materials as good choices for the development of “smart, paper-based machines, for instance, smart actuators.” Their work exploits single-atom-thick graphene sheets to create paper devices that spring to artificial life in response to humidity changes in the air around them. One such approach by professors Yong-Lai Zhang and Hong-Bo Sun of Jilin University, Changchun, China, could lead to a new category of fully autonomous, solar-powered paper sensors and MEMS devices. It can be engineered for extra rigidity, reflectivity, tensile strength, or other desirable properties, in combination with newer 2-D materials such as grapheme. It can be cut, folded, stacked, or rolled into useful 3-D shapes. Experimental paper devices capable of unattended motion are under development in a number of labs, and may someday have legs in commercial applications.Īs generations of origami artists and paper-plane designers can attest, a sheet of paper can become almost anything the creator wants it to be. Engineers are rediscovering the timeless practicality of paper in the fabrication of smart, low-cost robots that walk, scoot, and grasp all by themselves. But today, paper is propelling a different kind of movement: its own.
Over its 2,000-year monopoly as a medium for published thought, paper has provided the static catalyst for countless scholarly, social, religious, and political movements.
For an inanimate object, a piece of paper can pack a big punch.