Nanotubes assemble ! Rice introduces
‘Teslaphoresis’
Mike Williams
Reconfigured Tesla coil aligns, electrifies materials from
a distance
Scientists at Rice University have discovered that the strong
force field emitted by a Tesla coil causes carbon nanotubes to
self-assemble into long wires, a phenomenon they call
“Teslaphoresis.”
The team led by Rice chemist Paul Cherukuri reported its
results this week in ACS Nano.
Cherukuri sees this research as setting a clear path toward
scalable assembly of nanotubes from the bottom up.
The system works by remotely oscillating positive and negative
charges in each nanotube, causing them to chain together into
long wires. Cherukuri’s specially designed Tesla coil even
generates a tractor beam-like effect as nanotube wires are
pulled toward the coil over long distances.
Rice University chemist Paul Cherukuri, left, Texas A&M
graduate student Lindsey Bornhoeft, center, and Rice
research scientist Carter Kittrell show the power of
Teslaphoresis, which wirelessly lights their fluorescent
tubes. Tests with a customized Tesla coil revealed that
nanotubes within the field self-assemble into wires. Photo
by Jeff Fitlow
This force-field effect on matter had never been observed on
such a large scale, Cherukuri said, and the phenomenon was
unknown to Nikola Tesla, who invented the coil in 1891 with
the intention of delivering wireless electrical energy.
“Electric fields have been used to move small objects, but
only over ultrashort distances,” Cherukuri said. “With
Teslaphoresis, we have the ability to massively scale up force
fields to move matter remotely.”
The researchers discovered that the phenomenon simultaneously
assembles and powers circuits that harvest energy from the
field. In one experiment, nanotubes assembled themselves into
wires, formed a circuit connecting two LEDs and then absorbed
energy from the Tesla coil’s field to light them.
Cherukuri realized a redesigned Tesla coil could create a
powerful force field at distances far greater than anyone
imagined. His team observed alignment and movement of the
nanotubes several feet away from the coil. “It is such a
stunning thing to watch these nanotubes come alive and stitch
themselves into wires on the other side of the room,” he said.
Nanotubes were a natural first test material, given their
heritage at Rice, where the HiPco production process was
invented. But the researchers envision many other
nanomaterials can be assembled as well.
Lindsey Bornhoeft, the paper’s lead author and a biomedical
engineering graduate student at Texas A&M University, said
the directed force field from the bench-top coil at Rice is
restricted to just a few feet. To examine the effects on
matter at greater distances would require larger systems that
are under development. Cherukuri suggested patterned surfaces
and multiple Tesla coil systems could create more complex
self-assembling circuits from nanoscale-sized particles.
Cherukuri and his wife, Tonya, also a Rice alum and a
co-author of the paper, noted that their son Adam made some
remarkable observations while watching videos of the
experiment. “I was surprised that he noticed patterns in
nanotube movements that I didn’t see,” Cherukuri said. “I
couldn’t make him an author on the paper, but both he and his
little brother John are acknowledged for helpful discussions.”
Cherukuri knows the value of youthful observation – and
imagination – since he started designing Tesla coils as a
teen. “I would have never thought, as a 14-year-old kid
building coils, that it was going to be useful someday,” he
said.
Cherukuri and his team self-funded the work, which he said
made it more meaningful for the group. “This was one of the
most exciting projects I’ve ever done, made even more so
because it was an all-volunteer group of passionate scientists
and students. But because Rice has this wonderful culture of
unconventional wisdom, we were able to make an amazing
discovery that pushes the frontiers of nanoscience.”
The teammates look forward to seeing where their research
leads. “These nanotube wires grow and act like nerves, and
controlled assembly of nanomaterials from the bottom up may be
used as a template for applications in regenerative medicine,”
Bornhoeft said.
“There are so many applications where one could utilize strong
force fields to control the behavior of matter in both
biological and artificial systems,” Cherukuri said. “And even
more exciting is how much fundamental physics and chemistry we
are discovering as we move along. This really is just the
first act in an amazing story.”
Co-authors are Rice senior Aida Castillo; Rice research
scientists Carter Kittrell, Dustin James and Bruce Brinson;
Rice Distinguished Faculty Fellow Bruce Johnson; Thomas
Rybolt, chemistry department head and the UC Foundation
Professor at the University of Tennessee-Chattanooga; and
Preston Smalley of the Second Baptist School in Houston, who
worked on the project as a summer intern at Rice. Cherukuri
and Bornhoeft began the project while both were at the
University of Tennessee-Chattanooga.
Teslaphoresis of Carbon Nanotubes
Lindsey R. Bornhoeft, Aida C. Castillo, Preston R. Smalley,
Carter Kittrell, Dustin K. James, Bruce E. Brinson, Thomas
R. Rybolt, Bruce R. Johnson, Tonya K. Cherukuri, and Paul
Cherukuri
This paper introduces Teslaphoresis, the directed motion and
self-assembly of matter by a Tesla coil, and studies this
electrokinetic phenomenon using single-walled carbon nanotubes
(CNTs). Conventional directed self-assembly of matter using
electric fields has been restricted to small scale structures,
but with Teslaphoresis, we exceed this limitation by using the
Tesla coil’s antenna to create a gradient high-voltage force
field that projects into free space. CNTs placed within the
Teslaphoretic (TEP) field polarize and self-assemble into
wires that span from the nanoscale to the macroscale, the
longest thus far being 15 cm. We show that the TEP field not
only directs the self-assembly of long nanotube wires at
remote distances (>30 cm) but can also wirelessly power
nanotube-based LED circuits. Furthermore, individualized CNTs
self-organize to form long parallel arrays with high fidelity
alignment to the TEP field. Thus, Teslaphoresis is effective
for directed self-assembly from the bottom-up to the
macroscale.
Nanotubes assemble! Rice introduces
Teslaphoresis
Carbon nanotubes in a dish assemble themselves into a
nanowire in seconds under the influence of a custom-built
Tesla coil created by scientists at Rice University.