Sensor technology at Case can help uncover package tampering—or
tell you when it’s time to reel in that big fish
Researchers are developing materials that could
make consumers less susceptible to product tampering
or failures
February 18, 2005 | For more information: Laura
M. Massie (216)-368-4442
 In a world with an intensified need for security, Case Western Reserve
University researchers are developing materials that could make consumers
less susceptible to product tampering or failures. Using a mixture of
conventional polymers with small amounts of tailored fluorescent dyes,
Case researchers have discovered that the dyes function as natural,
molecular sensors, creating light-emitting polymer blends that show
mechanical stress by changing colors when a material is deformed.
The technology could be useful in a variety of applications that range
from early internal failure indicators in machinery and anti-counterfeiting
elements to tamper-resistant packaging of food or medicines. Their research
findings have appeared in several scholarly publications, most recently
the Journal Chemistry of Materials. The research is being funded by
the National Science Foundation and industry sources.
Christoph Weder, associate professor of macromolecular science and
engineering at the Case School of Engineering, and graduate engineering
students Brent Crenshaw and Jill Kunzelman are leading experiments in
their lab on the Case campus to further this technology. Crenshaw, who
has been working on the project for two years, points out that “only
a small amount of dye is needed to make the polymer glow and that the
polymer blend’s color contrast upon deformation is unparalleled.”
 Kunzelman, a first-year student, says it would be gratifying one day
to “see this technology used in everyday products.”
The thought isn’t far-fetched. Imagine being on a bass boat or
hip-deep in a beautiful river doing some fishing when a colorful light
emits from under the water – it’s either time to reel in
that largemouth bass quickly or attach another lure to your fishing
pole. Weder’s team created lab samples of a “smart” fishing
line based on light-emitting polymer materials. The color of the line
indicates when it’s been stressed too much. Weder, himself an
avid fisherman, is especially proud of that work.
The research team reports that they have successfully blended tailored
but readily available fluorescent dyes in minimal concentrations into
standard polymers, such as polyethylene and polypropylene, and discovered
that the dyes can serve as built-in sensors, which change their fluorescent
color and allow the researchers to trace the deformation of the material.
Weder says he is excited by the application potential for this simple,
yet groundbreaking technology his group discovered unexpectedly.
“This is so trivial, yet novel at the same time,” Weder
said. “No one has done this.”
Aside from Crenshaw and Kunzelman, Weder also employs two other graduate
students, two postdoctoral researchers and four engineering undergraduates
on his research team.
In addition, faculty and students in Case’s department of macromolecular
science and engineering are working on more than 20 projects involving
functional polymers, according to Alex Jamieson, professor and chair
of the department. Those projects include polymers for membranes in
fuel cells, electronic polymers with semiconducting properties and polymers
for biofunctional applications, such as those related to drug delivery
or biosensors. Weder’s deformation sensor technology project is
one of the department’s forays into photonic polymers.
Jamieson says he’s intrigued by Weder’s research into deformation
sensor technology. “It’s a novel approach to developing
polymeric blends that are sensitive to deformation,” he said. “It’s
a simple, yet very sensitive technique.”
Another exciting aspect of Weder’s research is how straightforward
it may be to commercialize.
“Some applicable dyes are affordable, easily made and can be
used in concentrations as low as 0.1 percent,” he said.
“There’s potential wherever polymers fulfill a structural
function,” he added, citing tamper-evident packaging tape as an
example. “We’re at a level of sophistication that would
allow us to produce a simple product now.”
For now, these applications are still possibilities. But, Weder adds,
with further commercial development, they could become reality in our
everyday lives.
About Case Western Reserve University
Case is among the nation's leading research institutions. Founded in 1826
and shaped by the unique merger of the Case Institute of Technology and Western
Reserve University, Case is distinguished by its strengths in education, research,
service, and experiential learning. Located in Cleveland, Case offers nationally
recognized programs in the Arts and Sciences, Dental Medicine, Engineering,
Law, Management, Medicine, Nursing, and Social Work. http://www.case.edu.
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