AUTONOMOUS
PAPER ROBOTS
As generations of origami artists and paper-plane designers can
attest, a sheet of paper can become almost anything the creator
wants it to be.
F
or an inanimate object, a piece of paper can pack a big punch. Over its 2,000-
“Graphene has exhibited a series of enticing
year monopoly as a medium for published thought, paper has provided the
physical/chemical properties such as high
static catalyst for countless scholarly, social, religious, and political movements.
electrical conductivity, transparency, biocom-
But today, paper is propelling a different kind of movement: its own. Engineers
patibility, mechanical flexibility, strength,
are rediscovering the timeless practicality of paper in the fabrication of smart, low-cost
and good stability”, Sun said, distinguish-
robots that walk, scoot, and grasp all by themselves. Experimental paper devices capable
ing graphene and related materials as
of unattended motion are under development in a number of labs, and may someday
good choices for the development of
have legs in commercial applications. As generations of origami artists and paper-plane
“smart, paper-based machines, for instance,
designers can attest, a sheet of paper can become almost anything the creator wants
smart actuators.”
it to be. It’s light, flexible, and cheap. It can be cut, folded, stacked, or rolled into useful
3-D shapes. It can be engineered for extra rigidity, reflectivity, tensile strength, or other
Sun, the director of JU’s Center for Ultrafast
desirable properties, in combination with newer 2-D materials such as grapheme.
Optoelectronic Technologies, said his
team’s ‘bots begin with graphene oxide
PAPER TRAIL
(GO) paper exposed to UV radiation from
One such approach by professors Yong-Lai Zhang and Hong-Bo Sun of Jilin University,
sunlight. “We recently found that focused
Changchun, China, could lead to a new category of fully autonomous, solar-powered
sunlight can reduce GO paper to some
paper sensors and MEMS devices. Their work exploits single-atom-thick graphene
extent. Therefore, one side of the GO paper
sheets to create paper devices that spring to artificial life in response to humidity
can be fully reduced due to the UV radia-
changes in the air around them.
tion-induced photochemical reactions, and
the other side can survive as pristine GO.”
This effect significantly alters the reduced
graphene oxide (RGO) surface’s waterrepelling capacity. Bilayers of RGO and
GO react differently when approached
with moisture, for example, an engineer’s
sweaty finger, he said. “In response to
moisture, the anisotropic water adsorption
causes it to curl in seconds.” The team has
adapted the technology into robots that
SELF FOLDING
instantly morph from flat paper strips
MOBILE PROTOTYPE
BY
M.I.T. & HARVARD
Gauge Newsletter
across a surface, as into more complex
autonomous claws that grasp and release
tiny objects. “Smart GO/RGO paper may find
broad applications in intelligent devices,”
Source: Harvard’s Wyss Institute.
16
into inchworm-like crawlers that scoot
University of Peradeniya