Newswise — In
the world of microtechnology, entire “machines,” so
tiny the naked eye can't see them, can be manufactured
to create things like sensors that deploy car air
bags. But conventional micromachine fabrication technologies
have been based on silicon, limiting them when it
comes to making complex, three-dimensional structures.
Now, a team of researchers, led by University Maryland
chemistry professor John T. Fourkas, has developed
a technique for creating microscopic structures from
multiple materials, paving the way for the creation
of entirely new types of micromachines.
In a paper appearing in the February 15 issue of
the Journal of the American Chemical Society ,
Fourkas and fellow researchers describe their invention
of a method that can incorporate a broad range of
materials, including metal, into structures fabricated
by multiphoton absorption polymerization (MAP), a
technique being developed by a number of groups around
the world.
MAP
uses a laser to harden a special liquid to create
microscopic 3-D structures that are composed of
a material similar to plexiglass. “It's akin to the
process that dentists use to harden composite fillings,” said
Fourkas, “except that the laser beam allows us to
do the hardening on a point by point basis.”
A
major drawback of MAP, however, is that it has
been limited to the creation of structures made
only of plastic. “For many applications it is necessary
to be able to include other materials as well,” says
Fourkas. “The ability to incorporate materials other
than plastic is a crucial step forward for multiphoton
fabrication.”
To demonstrate their technique, Fourkas and his
team deposited metal selectively on specific regions
of 3-D microstructures. By metal-coating a plastic
coil fabricated using MAP, they were able to create
and measure the properties of an inductor, a component
used in electronic devices such as cell phones, that
was a tenth as long as the diameter of a human hair.
“Although we demonstrated the deposition of metal
to make electrical devices, the same basic strategy
will work with other materials, such as biomolecules
or even glass,” Fourkas said. “This should make it
possible to create a whole new generation of microscopic
sensors, actuators, and other devices.”
Also participating in the research were postdoctoral
researcher Richard Farrer, graduate students Christopher
LaFratta, Linjie Lie, and Julie Praino, and collaborators
Michael Naughton of Boston College and Bahaa Saleh
and Malvin Teich of Boston University.
Read the online paper, with illustrations, in Journal
of the American Chemical Society :
http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/ja0583620
More about John Fourkas: http://www.chem.umd.edu/Faculty_Directory/faculty.php?id=55
More Fourkas visuals:
http://www.sciencentral.com/articles/view.php3?language=english&type=&article_id=218392371
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