Using a powerful electric force emitted by a Tesla coil, scientists at Rice University have made carbon nanotubes self-assemble to form a circuit linking two LEDs and then used the energy from that same field to power them. According to the researchers, the manipulation of matter on this scale has never before been observed and they've dubbed this phenomenon of remotely moving and assembling the nanotubes "Teslaphoresis."
As a nod to the technique of electrophoresis, a method used in laboratories to separate macromolecules using an applied charge to move proteins about, the Teslaphoresis moniker refers to a similar ability to move matter remotely with Tesla-coil electric fields.
"Electric fields have been used to move small objects, but only over ultrashort distances," says Rice University chemist Paul Cherukuri. "With Teslaphoresis, we have the ability to massively scale up force fields to move matter remotely. It is such a stunning thing to watch these nanotubes come alive and stitch themselves into wires on the other side of the room."
To achieve this feat, the researchers used an antenna attached to a Tesla coil to produce a high-voltage force field that was projected into free space. Compared by the team to a tractor beam, the process works by remotely oscillating positive and negative charges in each of the many thousands of single-walled carbon nanotubes placed within the field, which then causes them to link together. Long enough to be usefully used at a macro scale, the longest wire so far created is around 15 cm (6 in) long.
Able to align nanotubes at distances of up to several feet from the coil, the team's redesigned Tesla coil is able to create a very strong force field over distances much larger than previously seen, as well as power LEDs embedded in the circuits formed.The team believes that this ability for carbon nanotubes to self-organize into long parallel arrays could see Teslaphoresis being effectively used in the future to direct self-assembly from the microscale to produce macroscale objects.
Nikola Tesla, who invented his self-named coil around 1891 to produce high-voltage, low-current, high frequency alternating-current electric fields, had often toyed with ways to deliver wireless electrical energy, but would have had no idea that a derivative of his invention may one day be used to help self-assemble matter. Even Paul Cherukuri, who tinkered with Tesla coils as a child, did not see the possibilities until his team started experimenting with Tesla fields and nanoparticles..
"I would have never thought, as a 14-year-old kid building coils, that it was going to be useful someday," he says.
Given their electrical and mechanical properties, the team saw nanotubes as an obvious material to test first, particularly given the preemptive work at Rice University, where their bespoke single-walled carbon nanotube production process was invented (and usefully employed in a range of products, including ink-jet printed RFID tags). However the researchers believe that many other nanomaterials could be assembled using their Teslaphoresis process as well.
To help study and improve the effects on other such matter, and at greater distances, larger systems are currently being developed, where patterned surfaces and multiple Tesla coil systems are mooted that may help produce more complex self-assembling circuits from other nanoscale-sized particles.
"There are so many applications where one could utilize strong force fields to control the behavior of matter in both biological and artificial systems," says Cherukuri. "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."
The results of this research were recently published in the journal ACS Nano.
The short video below shows the self-assembling nanotubes in action.
Source: Rice University