14 / 82
A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A Y / J U N E 2 0 1 7
1 4
SURFACE ENGINEERING
DEPOSITION MODEL
PARTICULARLY DETAILED
Scientists at Lawrence Livermore
National Laboratory (LLNL), Calif.,
developed a computer model of the
process of electrophoretic deposition
(EPD) that offers an unprecedented
level of detail. EPD employs an electric
field to drive colloidal particles sus-
pended in a liquid out of solution onto
a conductive substrate, and the new
model tracks every single one of these
200-nm-diameter particles during the
entire procedure. Based on particle dy-
namics and running on LLNL’s Vulcan
supercomputing system, the model
was developed through dozens of sim-
ulations over a two-year period. The
team discovered that not only does
electrical field strength affect crystal
development, but surprisingly, salt con-
centration does as well.
The model could be used to better
understand deposition kinetics, thus
determining how fast to build and an-
ticipate resulting crystallinity, which
could impact how armor is produced
and how EPD coatings are applied. It
could also find application in photonics
science, which requires precise control
over crystallization. Until now, pho-
tonic crystallization has been accom-
plished through trial and error, but with
the new predictive model, virtual exper-
iments could replace months of work in
a lab.
llnl.gov.
ULTRATHIN FILM ON THE
SILVER SCREEN
Researchers at the University of
Michigan, Ann Arbor, reportedly laid
down the thinnest silver film to date,
making silver a potential player in the
touchscreen market as supplies of cur-
rent transparent conductors diminish.
Thanks to the addition of 6% alumi-
Professor L. Jay Guo holds a piece of
transparent silver film. Courtesy of
Joseph Xu/Michigan Engineering.
num, the new film is only 7 nm thick—
twice as thin as films made of pure
silver—and boasts tarnish resistance
as well. The researchers added an an-
tireflective coating that gives the film
92.4% transparency, which was main-
tained along with the film’s conductive
properties, even after several months.
In addition to its touchscreen po-
tential, the smooth silver coating could
serve as a formidable plasmodic wave-
guide—a material that transports infor-
mation in optical rather than electronic
form for faster data transfer. In fact, the
film can transmit surface plasmons fur-
ther than a centimeter, about 10 times
longer than other metal waveguides.
The silver films can also be layered
into a metamaterial hyperlens, which
can image objects too small to be seen
sharply with optical microscopes and
can also enable laser patterning—for
instance, etching transistors into silicon
chips—with much greater detail than
ordinary ultraviolet methods allow.
umich.edu.
BRIEF
Henkel,
Germany, will supply high-impact surfacing film (Loctite EA 9845 LC
AERO) to aerospace manufacturer
Textron Aviation Inc.,
Wichita, Kan., for
turboprop and business jet composite components. In addition to protecting
against lightning strikes, the new epoxy film adhesive is UV resistant and fills
voids, producing a smooth, paintable surface. Textron is the first aerospace man-
ufacturer to use the film, which is 30% lighter than alternatives.
henkel.com.Courtesy of Textron Aviation.
A new electrophoretic deposition model tracks every single particle during the entire
process, with each particle roughly the diameter of the smallest bacteria.