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A D V A N C E D
M A T E R I A L S
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P R O C E S S E S |
N O V E M B E R / D E C E M B E R
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SURFACE ENGINEERING
ROOM-TEMPERATURE ATOMIC
LAYER DEPOSITION
Researchers at the University of
Colorado Boulder developed a new
approach for synthesizing ultrathin ma-
terials at room temperature—a break-
through over industrial approaches that
require temperatures of 800°C or more.
The advance opens a path to creating a
host of previously unattainable thin-film
microelectronics, whose production by
conventional methods has been impos-
sible because many components lose
their critical functions when subjected
to high temperatures.
The new method is known as elec-
tron-enhanced atomic layer deposition
and was recently developed as part
of DARPA’s Local Control of Materials
Synthesis program. The team demon-
strated room-temperature deposition
of silicon and gallium nitride as well as
the ability to controllably etch specific
materials, leading to precise spatial
control in 3D. colorado.edu.
SPRAY-ON WATER PROOFING
Scientists at The Australian
National University (ANU) developed a
new spray-on material with a remark-
able ability to repel water. The coating
could eventually be used to waterproof
mobile phones, prevent ice from
forming on airplanes, and protect boat
hulls from corroding. The team com-
bined two plastics, one tough and one
flexible. “It’s like two interwoven fishing
nets, made of different materials,” says
Ph.D. student WilliamWong. The super-
hydrophobic coating is also transparent
and extremely resistant to ultraviolet
radiation. .
CREATING POLYMER BRUSHES
FOR ENGINEERED SURFACES
At the University of California,
Santa Barbara, researchers are looking
to greatly improve on polymer brush cre-
ation with a method of micron-scale sur-
face chemical patterning that not only
decreases the time and money spent
in manufacturing, but also adds versa-
tility to designs. Their method, called
“sequential stop-flow photopatterning,”
Galliumnitride film is deposited on silicon substrate at 27°C (80°F) using an
innovative process for depositing super thin films. Courtesy of University of
Colorado Boulder.
Scientists at ANU developed a new spray-
on, water-repellant material. Courtesy of
Stuart Hay/ANU.
features a new platform for functional-
izing and engineering surfaces with pat-
terned polymer brushes.
To create the brushes, a substrate
(with initiating molecules deposited)
is enclosed in a stop-flow cell and a
solution streamed in. Irradiation with
light can then initiate the reaction. A
separate photomask is positioned over
the top of the cell, allowing only some
light-activated growth. Next, the light is
turned off, the first solution is drained
from the cell, and a second one is
flowed in to functionalize the polymers.
Because neither the mask nor the sub-
strate has been moved, only the mole-
cules that have been exposed to light
are grown and functionalized. These
basic steps may be repeated with varia-
tions in the reactants, light source, sub-
strate positions, or photomask to create
polymer brush patterns in a single con-
tinuous process. For more information:
Christian Pester, ,
.
The stop-flow photopatterning method
enables intricate polymer brush patterns.
Courtesy of Christian Pester.