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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 | J U L Y / A U G U S T
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SURFACE ENGINEERING
NEW FILTER COULD HELP
IN OIL SPILLS
A new stainless steel mesh filter
created at The Ohio State University,
Columbus, could make a big difference
for future environmental cleanups. The
meshcoatingwaspartly inspiredby lotus
leaves, whose bumpy surfaces naturally
repel water but not oil. To create a coat-
ing that did the opposite, researchers
covered a bumpy surface with a polymer
embedded withmolecules of surfactant.
A fine dusting of silica nanoparticles was
then sprayed onto the stainless steel
mesh to create a randomly bumpy sur-
face while the polymer and surfactant
were layered on top. The silica, surfac-
tant, polymer, and stainless steel are all
non-toxic and relatively inexpensive, say
researchers. They estimate that a larger
mesh net could be created for less than
a dollar per square foot. Because the
coating is only a few hundred nanome-
ters thick, it is mostly undetectable. To
the touch, the coatedmesh does not feel
any bumpier than uncoated mesh. The
coatedmesh is a little less shiny, though,
because the coating is only 70% trans-
parent. .
IMPLANTABLE ELECTRODE
COATING IS GOOD AS GOLD
A team of researchers from Law-
rence Livermore National Laboratory
(LLNL) and University of California, Da-
vis, found that covering an implantable
neural electrode with nanoporous gold
could eliminate the risk of scar tissue
forming over the electrode’s surface.
The team demonstrated that the nano-
structure of nanoporous gold achieves
close physical coupling of neurons
by maintaining a high neuron-to-
astrocyte surface coverage ratio. Close
physical coupling between neurons
and the electrode plays a crucial role
in recording fidelity of neural electrical
activity.
Nanoporous gold, produced by
an alloy corrosion process, is a prom-
ising candidate to reduce scar tissue
formation on the electrode surface
solely through topography by taking
advantage of its tunable length scale.
“Nanoporous gold reduces scar cov-
erage but also maintains high neuro-
nal coverage in an in vitro neuron-glia
co-culture model,” says Juergen Bie-
ner at LLNL. “More broadly, the study
A neuronal network growing on a novel nanotextured gold electrode coating.
Courtesy of Ryan Chen/LLNL.
BRIEF
Whitford Corp., Elverson, Pa., established a new medical coatings group.
The company is a raw material supplier for catheter guide wire manufactur-
ers and coaters, as well as other biocompatible devices. To service all global
tiers of the medical supply chain, Whitford will implement an ISO 13485 compliant quality system, validate all levels
of manufacturing, and enhance quality control testing to ensure product quality and performance.
demonstrates a novel surface for sup-
porting neuronal cultures without the
use of culture medium supplements to
reduce scar overgrowth.” For more infor-
mation: Juergen Biener, 925.422.9081,
,
SURFACE-MODIFIED
NANOPARTICLES FOR
MULTIFUNCTIONAL COATINGS
The INM – Leibniz Institute for New
Materials, Germany, is using nanoparti-
cles to create multifunctional coatings.
These nanoparticles are specifically
adapted by small molecule surface
modification (SMSM). Depending on
which property is desired, the nanopar-
ticles can be surface modified with or-
ganic moieties. SMSM imparts specific
combinations of desired properties,
for example hydrophilic, hydrophobic,
adhesive, anti-adhesive, acidic, basic,
inert, or polymerizable.
Nanoparticles thus modified are
used to develop nanocomposites—
they combine the physical solid-state
properties of ceramics or semiconduc-
tors, for example, with classic poly-
mer-processing technology. Titanium
dioxide, barium titanate, indium-tin
oxide, or zirconium dioxide could be
used as nanoparticles. In addition to
the chemical intrinsic composition of
the nanoparticles and their SMSM sur-
face treatment, the properties that are
attainable for the desired coatings also
vary with the size and dispersal mode
of the nanoparticles.