Tag Archives: Victor García-López

Nanocar Race winners: The US-Austrian team

Sadly, I didn’t stumble across the news about the US-Austrian team sooner but it was not published until a May 8, 2017 news item on Nanowerk,

Rice University chemist James Tour and his international team have won the first Nanocar Race.

The Rice and University of Graz team finished first in the inaugural Nanocar Race in Toulouse, France, April 28, completing a 150-nanometer course — roughly a thousandth of the width of a human hair — in about 1½ hours. (The race was declared over after 30 hours.)

Interestingly the Rice University news release announcing the win was issued prior to the ‘winning’ Swiss team’s and it explains why the Swiss team was declared a co-winner despite the additional hours (6.5 hours as compared to 1.5 hours [see my May 9, 2017 posting: Nanocar Race winners! where the Swiss appear to claiming they raced 38 hours]) before completing the race. From an April 28, 2017 Rice University news release,

The team led by Tour and Graz physicist Leonhard Grill deployed a two-wheeled, single-molecule vehicle with adamantane tires on its home track in Graz, Austria, achieving an average speed of 95 nanometers per hour. Tour said the speed ranged from more than 300 to less than 1 nanometer per hour, depending upon the location along the course.

The Swiss Nano Dragster team finished next, five hours later. But organizers at the French National Center for Scientific Research declared them a co-winner of first place as they were tops among teams that raced on a gold track.

Because the scanning tunneling microscope track in Toulouse could only accommodate four cars, two of the six competing international teams — Ohio University and Rice-Graz — ran their vehicles on their home tracks (Ohio on gold) and operated them remotely from the Toulouse headquarters.

The Dipolar Racer designed at Rice.

The Dipolar Racer designed at Rice.

Five cars were driven across gold surfaces in a vacuum near absolute zero by electrons from the tips of microscopes in Toulouse and Ohio, but the Rice-Graz team got permission to use a silver track at Graz. “Gold was the surface of choice, so we tested it there, but it turns out it’s too fast,” Grill said. “It’s so fast, we can’t even image it.”

The team got permission from organizers in advance of the race to use the slower silver surface, but with an additional handicap. “We had to go 150 nanometers around two pylons instead of 100 nanometers since our car was so much faster,” Tour said.

Tour said the race directors used the Paris-Rouen auto race in 1894, considered by some to be the world’s first auto race, as precedent for their decision April 29. “I am told there will be two first prizes regardless of the time difference and handicap,” he said.

The Rice-Graz car, called the Dipolar Racer, was designed by Tour and former Rice graduate student Victor Garcia-Lopez and raced by the Graz team, which included postdoctoral researcher and pilot Grant Simpson and undergraduate and co-pilot Philipp Petermeier.

The silver track under the microscope. Two Rice nanocars are in the blue circle at top. The lower car was the first to run the race, finishing in an hour-and-a-half. The top car was put through the course later, finishing in 2 hours.

The silver track under the microscope. Two Rice nanocars are in the blue circle at top. The lower car was the first to run the race, finishing in a 1½ hours. The top car was put through the course later, finishing in 2 hours. Click on the image for a larger version.

The purpose of the competition, according to organizers, was to push the science of how single molecules can be manipulated as they interact with surfaces.

“We chose our fastest wheels and our strongest dipole so that it could be pulled by the electric field more efficiently,” said Tour, whose lab has been designing nanocars since 1998. ‘We gave it two (side-by-side) wheels to minimize interaction with the surface and to lower the molecular weight.

“We built in every possible design parameter that we could to optimize speed,” he said.

While details of the Dipolar Racer remained a closely held secret until race time, Tour and Grill said they will be revealed in a forthcoming paper.

“This is the beginning of our ability to demonstrate nanoscale manipulation with control around obstacles and speed and will pave the way for much faster paces and eventually for carrying cargo and doing bottom-up assembly.

“It’s a great day for nanotechnology,” Tour said. “And a great day for Rice University and the University of Graz.”

Clearly all the winners were very excited. Still, there’s a little shade being thrown (one of the scientists is just a tiny bit miffed) as you can see in James Tour’s quote given after noting the US-Austrian racer was too fast for the gold surface so the team used the slower silver surface and were given another handicap. As per the Rice University news release: ““I am told [emphasis mine] there will be two first prizes regardless of the time difference and handicap,” he said.” Of course, the Swiss team’s news release didn’t mention the US-Austrian team’s speedier finish nor did it name (Dipolar Racer) the US-Austrian racer. As I noted before, scientists are people too.

A 244-atom submarine powered by light

James Tour lab researchers at Rice University announce in a Nov. 16, 2015 news item on Nanowerk,

Though they’re not quite ready for boarding a lá “Fantastic Voyage,” nanoscale submarines created at Rice University are proving themselves seaworthy.

Each of the single-molecule, 244-atom submersibles built in the Rice lab of chemist James Tour has a motor powered by ultraviolet light. With each full revolution, the motor’s tail-like propeller moves the sub forward 18 nanometers.
And with the motors running at more than a million RPM, that translates into speed. Though the sub’s top speed amounts to less than 1 inch per second, Tour said that’s a breakneck pace on the molecular scale.

“These are the fastest-moving molecules ever seen in solution,” he said.

Expressed in a different way, the researchers reported this month in the American Chemical Society journal Nano Letters that their light-driven nanosubmersibles show an “enhancement in diffusion” of 26 percent. That means the subs diffuse, or spread out, much faster than they already do due to Brownian motion, the random way particles spread in a solution.

While they can’t be steered yet, the study proves molecular motors are powerful enough to drive the sub-10-nanometer subs through solutions of moving molecules of about the same size.

“This is akin to a person walking across a basketball court with 1,000 people throwing basketballs at him,” Tour said.

A Nov. 16, 2015 Rice University news release (also on EurekAlert), which originated the news item, provides context and details about the research,

Tour’s group has extensive experience with molecular machines. A decade ago, his lab introduced the world to nanocars, single-molecule cars with four wheels, axles and independent suspensions that could be “driven” across a surface.

Tour said many scientists have created microscopic machines with motors over the years, but most have either used or generated toxic chemicals. He said a motor that was conceived in the last decade by a group in the Netherlands proved suitable for Rice’s submersibles, which were produced in a 20-step chemical synthesis.

“These motors are well-known and used for different things,” said lead author and Rice graduate student Victor García-López. “But we were the first ones to propose they can be used to propel nanocars and now submersibles.”

The motors, which operate more like a bacteria’s flagellum than a propeller, complete each revolution in four steps. When excited by light, the double bond that holds the rotor to the body becomes a single bond, allowing it to rotate a quarter step. As the motor seeks to return to a lower energy state, it jumps adjacent atoms for another quarter turn. The process repeats as long as the light is on.

For comparison tests, the lab also made submersibles with no motors, slow motors and motors that paddle back and forth. All versions of the submersibles have pontoons that fluoresce red when excited by a laser, according to the researchers. (Yellow, sadly, was not an option.)

“One of the challenges was arming the motors with the appropriate fluorophores for tracking without altering the fast rotation,” García-López said.

Once built, the team turned to Gufeng Wang at North Carolina State University to measure how well the nanosubs moved.

“We had used scanning tunneling microscopy and fluorescence microscopy to watch our cars drive, but that wouldn’t work for the submersibles,” Tour said. “They would drift out of focus pretty quickly.”

The North Carolina team sandwiched a drop of diluted acetonitrile liquid containing a few nanosubs between two slides and used a custom confocal fluorescence microscope to hit it from opposite sides with both ultraviolet light (for the motor) and a red laser (for the pontoons).

The microscope’s laser defined a column of light in the solution within which tracking occurred, García-López said. “That way, the NC State team could guarantee it was analyzing only one molecule at a time,” he said.

Rice’s researchers hope future nanosubs will be able to carry cargoes for medical and other purposes. “There’s a path forward,” García-López said. “This is the first step, and we’ve proven the concept. Now we need to explore opportunities and potential applications.”

Here’s a link to and a citation for the paper,

Unimolecular Submersible Nanomachines. Synthesis, Actuation, and Monitoring by Víctor García-López, Pinn-Tsong Chiang, Fang Chen, Gedeng Ruan, Angel A. Martí, Anatoly B. Kolomeisky, Gufeng Wang, and James M. Tour. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.5b03764 Publication Date (Web): November 5, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

There is an illustration of the 244-atom submersible,

Rice University scientists have created light-driven, single-molecule submersibles that contain just 244 atoms. Illustration by Loïc Samuel

Rice University scientists have created light-driven, single-molecule submersibles that contain just 244 atoms. Illustration by Loïc Samuel