with even greater abilities. “You could
add sensing, maybe actuating capabilities, into your structure,” Qi says. One
application might be used as the skin
of an airplane or the heat-shielding
tiles on a space shuttle; the material
might be able to sense damage and alter its shape to self-heal, forming a
temporary patch to protect the craft
until it can be properly repaired.
Olguin argues that another area of
research—3D bioprinting—might also
be considered a form of 4D printing.
Researchers are trying to find ways to
incorporate living cells into 3D printing, depositing them along with a
soft matrix to form artificial organs or
biorobots. In that case, Olguin says, the
cells that grow and change over time
bring in the fourth dimension.
The U.S. military believes 4D print-
ing has potential. The U.S. Army Re-
search Office last fall gave an $855,000
grant to a trio of researchers from the
University of Pittsburgh, Harvard, and
the University of Illinois to develop
materials that would be useful to sol-
diers. Lead researcher Anne Balazs, a
chemical engineer at Pittsburgh, says
the group is concentrating on manipu-
lating materials at a microscopic level
to achieve desired properties, which
might involve active camouflage or pro-
tection from shrapnel.
Though the field of 4D printing is
still in its infancy, the researchers say it
is likely to be only a few years before 3D
printed objects that change over time
start making their way into everyday
use. “The momentum’s there,” Qi says.
“This field is developing really fast.”
Ge, Q., Qi, H.J., Dunn, M.
Active Materials by Four-Dimensional
Printing, Appl. Phys. Lett 103, 2013.
4D Printing: Multi-Material Shape Change,
Arch. Design 84 ( 1) 116-121 (2014)
Goldstein, S.C., Campbell, J.D., Mowry, T.C.
Programmable Matter, Computer 28 ( 6),
Change Generation: Skylar Tibbits
Neil Savage is a science and technology writer based in
© 2014 ACM 0001-0782/14/06 $15.00
lot of freedom,” he says. “You can control what kind of deformation you get.”
Depending on the material used
and the design of the object, the temperature difference needed to induce a
change can be fairly small. One potential use Qi sees is for a medical device
such as a stent, which can be built in
compact form for easy placement inside an artery; once in place, the body’s
own heat would make it expand to fit.
So far, these researchers are working exclusively with polymers. Though
it is possible to get some shape-chang-ing behavior with a single material
and clever design, it works better with
multiple materials. The only 3D printers currently on the market that are
capable of printing multiple materials
come from Stratasys, and those print
using only different types of polymer.
Many researchers are working on ways
to print more disparate materials together so that they could, for example,
deposit metal wires inside ceramics, or
build plastic parts with embedded circuitry. Because the processes for printing with different materials vary widely—the temperatures that melt metal
to form parts also vaporize plastic, and
inkjet printers that work nicely with
one type of ink quickly clog with another—it could be a few years before more
complex material designs are realized.
Being able to incorporate more capabilities, including electronics, in a
3D printed object could lead to devices
that another area
also be considered a
form of 4D printing.
DUAL HONORS FOR
Purdue University computer
science professor Eugene H.
Spafford, a recognized leader in
the information security field,
recently was inducted into the
National Security Hall of Fame.
Spafford, who also is executive
director of Purdue’s Center
for Education and Research
in Information Assurance and
Security, also was selected to
receive the Harold F. Tipton
Lifetime Achievement Award.
Spafford, a Purdue faculty
member since 1987, was one of
the first Morrill Award recipients
at Purdue University. He is chair
of ACM’s U.S. Public Policy
Council (USACM), a Fellow of the
ACM, a Fellow of the American
Association for the Advancement
of Science, a Fellow of the Institute
for Electrical and Electronics
Engineers, and charter recipient of
the Computer Society’s Golden
IEEE COMPUTERS AND
George Varghese, a principal
researcher at Microsoft Research
Redmond, recently was named the
2014 recipient of IEEE’s Koji Ko-
bayashi Computers and Communi-
cations Award, “for contributions
to the field of network algorithmics
and its applications to high-speed
The award is presented for
outstanding contributions to the
integration of computers and
Previous recipients include
ACM president Vint Cerf, ACM
Fellow Robert Kahn, and ACM
Software System Award recipient
ROYAL SOCIETY OF CANADA
NAMES AHO 2013 FELLOW
The Royal Society of Canada
(RSC), a leading Canadian society
of distinguished scholars, artists,
and scientists, named computer
scientist Alfred Vaino Aho as one
of its 2013 Fellows.
The RSC said Aho, who
holds the Lawrence Gussman
Chair of Computer Science
at Columbia University,
“has made fundamental
contributions to string
searching, databases, formal
languages, compilation, and
pattern matching. His research
is used daily in millions of
Aho is a Fellow of the American
Academy of Arts and Sciences,
the American Association for the
Advancement of Science, ACM,
Bell Labs, and IEEE.
Computer Science Awards, Appointments