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Simple spray gun technique
makes self-assembling nanoparticle films
Researchers at Kyushu University, Japan, devel-
oped a simple approach to apply a surface coating of
thin, flat nanoplatelets using a common spray gun
that can be purchased from an art supply store to cre-
ate a surface coating in which nanoplatelets sponta-
neously self-assemble into “nanowalls.” The nanowalls
act as rigid barriers that prevent oxygen from reach-
ing the surface, and are effective at low and high hu-
midity levels. Using this scalable and simple
processing method, researchers achieved extremely
fine and highly ordered nanoscale features that are
conventionally achieved with complex and energy-
intensive manufacturing techniques. For more
information: H-J Sue, 979.845.5024, ,
.
Reducing solar panel glare
The glare from solar farms could be a thing of the past, thanks to scientists at Loughbor-
ough University, UK. They developed a multilayer anti-reflection (AR) coating for glass sur-
faces, which reduces the sun’s reflection from photovoltaic panels while at the same time
improving their efficiency. The coating is applied using the same technology as that used to
deposit AR coatings on spectacles. The design, developed by Michael Walls, Piotr Kaminski,
and Fabiana Lisco, reduces reflection by more than 70% across the wavelength range ac-
cepted by PV panels and consists of only four alternate layers of zirconium oxide and silicon
dioxide, with the whole stack less than 300 nm thick. Coatings are deposited using magnetron
sputtering by a machine developed by UK-based Power Vision Ltd. For more information:
Michael Walls, +44.0.1509.635201, , .
Brush-turkey eggs inspire germ-resistant coatings
The Australian brush-turkey buries its eggs in rotting vegetation to incubate them.
While bacterial decomposition heats the eggs, it does not infect them. University of Akron,
Ohio, scientists found that the eggshell surface—dotted with nanospheres—blocks bacte-
ria. Because water provides a breeding ground for bacteria, researchers applied water to the
eggshell to determine its hydrophobicity. Like water on a freshly polished car, water on the
brush-turkey egg beaded up. “Most bacteria grow best when water is available, and these
eggs appear to reduce water on their surface,” says visiting assistant professor Liliana
D’Alba, noting that conversely, water spreads across the shell surface of eggs without nanos-
pheres, such as chicken eggs. The eggs’ rough surface could serve double-duty, preventing
bacteria from infecting the eggs by both limiting water and averting bacteria, according to
researchers. The eggshells’ robust surface provoked ideas for developing a synthetic coat-
ing to benefit medical, food processing, and manufacturing industries. .
Biologist Liliana D’Alba watches an
Australian brush-turkey bury its eggs in
rotting vegetation.
ADVANCED MATERIALS & PROCESSES • JULY 2014 13
SURFACE ENGINEERING
news
industry
briefs
Ortho Development, Draper, Utah,
received U.S. FDA approval for its
Ovation Tribute hip stem intended
for cementless use in total hip
replacement and hemiarthroplasty
procedures. The hip stem, a
femoral hip prosthesis, reduces
bone loss and length of surgery.
The stem includes a minimal
broach-only instrumentation
platform and is available in a
range of sizes with both standard
and extended neck offset options
in order to provide options for
various patient needs. Proximal
body surface of the hip stem is
coated with titanium plasma spray
for solid, long-term fixation.
.
Ovation Tribute hip stem for
cementless use in total hip
replacement and
hemiarthroplasty procedures.
Courtesy of PRNews/Ortho
Development Corp.
Dow Corning, Midland, Mich.,
introduced MAINCOTE IC Acrylic
Resins, a new category of liquid
insulation coatings that offers low
thermal conductivity in an easy
spray application. Thermal
insulation coatings formulated
with the new resins offer a
solution to unintended heat loss
and corrosion under insulation
(CUI). The resins are designed for
use with low thermal conductivity
fillers, and coatings formulated
with them can replace the thick
mechanical insulation that can
mask CUI. Fiberglass and other
industrial insulation materials
typically require a separate
moisture barrier or jacketing to
prevent corrosion issues.
A simple approach applies a surface
coating of thin, flat nanoplatelets
using a common spray gun to
create a surface coating in which
nanoplatelets spontaneously self-
assemble into nanowalls.
Ranga Pitchumani, professor of mechanical engineering at Virginia Tech, Blacksburg, de-
veloped a type of coating that has little to no affinity for water and emulates the Lotus effect.
Using a two-step technique, “We produced a low cost and simple approach for coating metal-
lic surfaces with an enduring superhydrophobic (strong water repellant) film of copper,” ex-
plains Pitchumani. This template-free process allows the coating material to be made of the
same material as the substrate, preserving its thermal and electrical properties. .