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These images are of a triblock
copolymer membrane formed by combining three polymers, where the
blue regions depict conducting channels. From left: the membrane’s
lattice-like framework, followed by a 3-D view of the copolymer
network, then a simulated 2-D view of the copolymer membrane and
an actual view of the membrane with a transmission electron
microscope.
Image © by Thomas H. Epps III,
University of Delaware
Thomas Epps III, assistant
professor of chemical engineering at the University of Delaware,
is developing nanoscale membranes for the next generation of
materials, from fuel cells to protective clothing.
Photo © by Kathy F. Atkinson,
University of Delaware |
"Thomas Epps is a highly skilled scientist
with great energy, enthusiasm and dedication to research and teaching,
which are hallmarks of the career award," Eric Kaler, the Elizabeth
Inez Kelley Professor of Chemical Engineering and dean of UD's College
of Engineering, said. "We congratulate him on this well-deserved honor."
The materials that Epps is developing contain
structures that are a thousand times smaller than the diameter of a
human hair and represent the "best of both worlds" because they
combine the properties of two or more different polymers.
"An example is to take poly(isoprene), which is
found in a rubber band, and chemically bind it to poly(styrene), which
is found in a Styrofoam cup," Epps explained. "By combining these two
polymers, you would get the properties of both--resulting in an
elastic, rubbery material with structural and thermal stability, such
as a passenger car tire."
Epps says the beauty of block copolymers is that
they self-assemble, which makes them a cheaper alternative to the
laser-generated templates currently used in semiconductor fabrication,
and that also enhances their potential for membrane and separation
applications.
"There are plenty of applications for these
nano-networks, such as conducting membranes for methanol and hydrogen
fuel cells, thin polymer barriers on military clothing that are
resistant to biological and chemical agents, or new separation
membranes to remediate harmful materials from car exhaust," Epps noted.
Epps and his students are working to understand the
nano-sized features of the block copolymers by controlling their
structure and orientation--a process that requires a knowledge of
chemistry, chemical engineering, polymer science and materials science.
In Epps' lab, graduate students Mary Vukmir and
Maeva Tureau, along with undergraduate Paul Brigandi, are examining
the block copolymer materials for mechanical strength, solvent
resistance and conductivity using such high-tech tools as transmission
electron microscopy and X-ray scattering, which allow the scientists
to visualize nanoscale structures. Graduate student Julie Lawson and
undergraduate Tom Scherr are discovering new methods of creating
nanotemplates for applications such as hard-disk-drive arrays, using
atomic force microscopy and other techniques.
"We do everything from synthesizing the copolymer
to characterizing its structure, studying its nanoscale and microscale
assembly, and benchmarking it for applications," Epps said.
Growing up near Richmond, Va., Epps said he was
always interested in math and science. Although his father is a
retired chemistry professor and his mother is an accounting professor,
they never pushed him to pursue their respective fields. What really
turned on his interest in scientific research, particularly in
polymers, was his participation in the Virginia Governor's School
Program when he was a junior in high school.
"Our project was to test polymer films as solar
panel covers for space environments," Epps said. "What was so exciting
about it was that we didn't just make the films for the panels," he
noted. "We got to mount the films on the remote manipulator arm of the
space shuttle and recover them for analysis following a space flight."
A component of Epps' NSF award is devoted to
increasing the participation of under-represented groups in science
and engineering.
Epps is partnering with professors Andrew Goudy and
Preston Hayward at Delaware State University to incorporate polymer
science and engineering into their courses. He also will welcome
students from Delaware State to his UD lab this summer for hands-on
research.
As an affiliated faculty member, Epps also is
working in partnership with the Delaware Biotechnology Institute to
involve qualified UD minority students in the American Chemical
Society's Scholars Program. Epps is an alumnus of the program, having
received its scholarship award in 1995.
In other outreach efforts, Epps, Sharon Anderson,
undergraduate services coordinator, and others from UD's chemical
engineering department are working with Newark High School to expose
students to chemical engineering and various career paths in the field.
"I want to be able to walk into a classroom and
show that anyone who wants to can become a chemical engineer and be
successful," Epps said.
Epps said he's glad he chose to join the UD faculty.
He will celebrate his first anniversary at UD in June.
"The support, collegiality and reputation of the
faculty were extremely important to my decision to come here, as well
as the quality of the students and the University's commitment to
families," he said, noting that his wife, who does energy trading for
a major bank, already has given two lectures related to "green"
engineering at UD.
"I chose academia over industry because here you
have the opportunity to influence young people, and you also have the
ability to tackle the problems that you want to pursue," he noted.
Epps received his bachelor's and master's degrees
in chemical engineering from the Massachusetts Institute of Technology
and his doctorate in chemical engineering from the University of
Minnesota.
Before joining UD, he completed a National Research
Council Postdoctoral Fellowship at the National Institute for
Standards and Technology. |
