2/2014 http://www.business-spotlight.de 81TRANSIENT ELECTRONICS TECHNOLOGYtended to last forever with no loss in
their ability to function. “However,”
he says, “when we looked to the fu-
ture we realized that there was an op-
portunity for a new electronics —
transient electronics — that might
function properly for a limited
amount of time and then disappear.”There are a number of problems
that Rogers has to overcome, how-
ever, such as whether electronics that
dissolve in our bodies harm our
health, or how devices that dissolve in
water can be mass-produced in a pro-
duction process that normally uses a
lot of water.
Further ahead lies another signifi-
cant problem: how to get these de-
vices to die on demand or in sub-
stances other than water, so that the
Pentagon doesn’t have to wait for
rain before the proof of its secret mis-
sion disappears.
To solve such problems, Rogers has
been experimenting with materials
commonly found in semiconductors;
for example, by using silicon layers
so thin that they will dissolve in wa-
ter, and by using magnesium rather
than copper to conductelectricity.
The whole circuit is enclosed in layers
of silk, and the thickness of this silk
substrate determines how long the
circuit exists. The device is wirelessly
connected to an external power
source.
Other materials, including zinc ox-
ide and bioresorbablepolymers, can
be used in transient technology as
well, giving Rogers “a wide palette of
materials to work from”. The first de-
vices his team developed were smalland thin, but only partially
transient, explains Rogers.
“The actual eureka moment
came when we had full
transiencein everything.”
Rogers’s demonstrations
are impressive, says Profes-
sor Michael McAlpine, who
teaches mechanical engi-
neeringat Princeton Uni-
versity, but adds that being
able to control exactly
when the sensors will live
or die, called “tunability”,
is essential to the success of
the technology.
There could be triggersother than
water that could also cause the device
to dissolve, suggests Michael Dickey,
a specialist in biomolecular technolo-
gy at North Carolina State Universi-
ty. Triggers such as a remote signal
are particularly important for wider
use of the technology, whether this is
in the body or recording the clean-up
of an oil spill or troop movements
during a battle.“The dissolutionrate ofthe layers,
the types of materials used to conduct
electricity and the types of materials
that can be used in the transistors”
may be limiting factors, says Teri W.
Odom, professor of chemistry at
Northwestern University in Illinois.
Whether or not the power source can
be built on the electronics themselves
may be another factor, Odom adds.
While Rogers accepts that signifi-
cant questions remain, including how
well wireless devices function when
deep inside the body, he believes tran-
sience in dry conditions is possible.“I did eat one device,
and I didn’t feel a thing. It just
dissolved in my mouth”
Other triggers Rogers suggests are
“mechanical shocks, temperature
change, light exposureand chemical-
biological”, all of which are more
suitable than water in many situa-
tions. Quietly confident, he states:
“It is still very early stages, but we are
very optimistic that transient elec-
tronics will represent a big break-
through.”
© Guardian News & Media 2013bioresorbable bioresorbierbar
[)baIEUri(sO:bEb&l]
conduct sth. [kEn(dVkt] etw. leiten
copper [(kQpE] Kupfer
dissolution [)dIsE(lu:S&n] Auflösung
eureka moment Aha-Erlebnis; hier:
[ju&(ri:kE )mEUmEnt] Wendepunkt
layer [(leIE] Schicht
light exposure Lichteinwirkung
[(laIt Ik)spEUZE]
mechanical engineering Maschinenbau
[mI)kÄnIk&l endZI(nIErIN]
remote signal Steuersignal
[ri)mEUt (sIgn&l]
(remote entfernt)
semiconductor Halbleiter
[)semikEn(dVktE]
transience Kurzlebigkeit, Ver-
[(trÄnziEns] gänglichkeit
tunability [)tju:nE(bIlEti] AbstimmbarkeitJohn A. Rogers: making nothing out of something■BS
M. J. Granse80-81 TechmainE 2_14 14.01.14 13:53 Seite 81