58 DISCOVERMAGAZINE.COM
THIS PAGE FROM LEFT: AFFOA; SAM OGDEN. OPPOSITE: SAM OGDENconverts an electrical signal into a sound.
The opposite is also possible. The fiber can
be a microphone as well.”
Scientists have known about the
piezoelectric effect since 1880 and have
exploited the phenomenon in electronics
for a century, not only for sound but
also to exert and detect pressure. By
introducing piezoelectricity into a thread
that can be woven into a garment, Fink’s
group is transplanting a hundred years of
innovation into a new domain, endowing
fabrics with capabilities that could be
achieved previously only with devices that
people strap on or carry. Those devices, such as health
and fitness wearables, are limited by the fact that they’re
accessories. “Stuff we wear is called clothes,” quips Fink.
He believes this is more than a trivial distinction.
Our clothing has as much as 20 square feet of external
surface area, touching nearly every part of the body. That
means a piezoelectric textile could potentially hear our
surroundings, sense our movements and monitor internal
organs, such as our heart and lungs, with unprecedented
fidelity. It could also generate energy as we walk.
And piezoelectricity is only one of many electronic
capacities Fink’s lab is systematically mastering. Michael
Rein, a former grad student of Fink’s and now a senior
product engineer at AFFOA, has been drawing fibers that
contain tiny diodes, semiconductors that can alternately
emit or detect light. Woven into a fabric, they’ll be able
to electronically change a garment’s appearance or allow
for remote communication. In his thesis work, Rein
demonstrated that these functional fibers are washable — an
important milestone on the road from lab to marketplace.
As with any electronics, multiple components willbe able to do far more collectively. For
instance, by combining Rein’s diode fibers
with Khudiyev’s piezoelectrics, “you could
communicate at a distance,” observes
Fink’s grad student Grena. The diodes
could detect a voice-controlled laser beam
and make the piezoelectric fabric vibrate so
that troops could hear their commander’s
orders on a chaotic battlefield. Conversely,
vital signs measured by piezoelectric fibers
could be relayed to a medic by light-
emitting diodes (LEDs) on a wounded
soldier’s uniform. Grena also foresees
advantages in terms of scale, especially for
sensor networks. Fibrous electronics can be stretched very
thin to extend over vast distances. A piezoelectric mesh
could take large-scale measurements, like bridge strain or
ocean currents.
At the opposite extreme, Anikeeva is applying Fink’s
fiber-drawing technique to neuroscience. Her flexible
filaments take advantage of the miniaturization afforded
by fiber drawing, combining optical waveguides with
conductive electrodes and fluid channels to create a probe
thinner than a human hair. A single probe can deliver
drugs and measure neural activity in a brain or spinal cord
without damaging tissue. It can even stimulate neurons
that have had their DNA modified to respond to light,
making it a powerful and versatile tool in the emerging
field of optogenetics. “The fiber-drawing process,” says
Anikeeva, “is the enabling capability.”CLOSING THE GAP
At MIT’s Computer Science and Artificial Intelligence
Lab, Fink shows off some of the first products developed
by AFFOA. He presents backpacks with unique barcode-Above, a sample from Fink’s lab reveals
functional fibers interwoven into a lightweight
fabric. At right, Michael Rein, a senior product
engineer at AFFOA, examines a fiber emerging
from the draw tower. Rein’s work has shown the
fibers are washable, an important milestone.OUR CLOTHING
HAS AS MUCH AS
20 SQUARE FEET
OF EXTERNAL
SURFACE AREA,
TOUCHING NEARLY
EVERY PART OF
THE BODY.