In research published online September 4 in Nature Nanotechnology, the Tufts team reports an electric motor that measures a mere 1 nanometer across, groundbreaking work considering that the current world record is a 200 nanometer motor. A single strand of human hair is about 60,000 nanometers wide.
Chemists at Tufts University have developed the world's first single molecule electric motor, which may potentially create a new class of devices that could be used in applications ranging from medicine to engineering. The molecular motor was powered by electricity from a state of the art, low-temperature scanning tunneling microscope. This microscope sent an electrical current through the molecule, directing the molecule to rotate in one direction or another. The molecule had a sulfur base (yellow); when placed on a conductive slab of copper (orange), it became anchored to the surface. The sulfur-containing molecule had carbon and hydrogen atoms radiating off to form what looks like two arms (gray); these carbon chains were free to rotate around the central sulfur-copper bond. The researchers found that reducing the temperature of the molecule to five Kelvin (K), or about minus 450 degrees Fahrenheit (ºF), enabled them to precisely impact the direction and rotational speed of the molecular motor The Tufts team plans to submit this miniature electric motor to the Guinness World Records. The research was published online Sept. 4 in Nature Nanotechnology. Credit: Heather L. Tierney, Colin J. Murphy, April D. Jewell, Ashleigh E. Baber, Erin V. Iski, Harout Y. Khodaverdian, Allister F. McGuire, Nikolai Klebanov and E. Charles H. Sykes.
According to E. Charles H. Sykes, Ph.D., associate professor of chemistry at Tufts and senior author on the paper, the team plans to submit the Tufts-built electric motor to Guinness World Records.
"There has been significant progress in the construction of molecular motors powered by light and by chemical reactions, but this is the first time that electrically-driven molecular motors have been demonstrated, despite a few theoretical proposals," says Sykes. "We have been able to show that you can provide electricity to a single molecule and get it to do something that is not just random."
Sykes and his colleagues were able to control a molecular motor with electricity by using a state of the art, low-temperature scanning tunneling microscope (LT-STM), one of about only 100 in the United States. The LT-STM uses electrons instead of light to "see" molecules.
The team used the metal tip on the microscope to provide an electrical charge to a butyl methyl sulfide molecule that had been placed on a conductive copper surface. This sulfur-containing molecule had carbon and hydrogen atoms radiating off to form what looked like two arms, with four carbons on one side and one on the other. These carbon chains were free to rotate around the sulfur-copper bond.
The team determined that by controlling the temperature of the molecule they could directly impact the rotation of the molecule. Temperatures around 5 Kelvin (K), or about minus 450 degrees Fahrenheit (ºF), proved to be the ideal to track the motor's motion. At this temperature, the Tufts researchers were able to track all of the rotations of the motor and analyze the data.
While there are foreseeable practical applications with this electric motor, breakthroughs would need to be made in the temperatures at which electric molecular motors operate. The motor spins much faster at higher temperatures, making it difficult to measure and control the rotation of the motor.
"Once we have a better grasp on the temperatures necessary to make these motors function, there could be real-world application in some sensing and medical devices which involve tiny pipes. Friction of the fluid against the pipe walls increases at these small scales, and covering the wall with motors could help drive fluids along," said Sykes. "Coupling molecular motion with electrical signals could also create miniature gears in nanoscale electrical circuits; these gears could be used in miniature delay lines, which are used in devices like cell phones."
The Changing Face of Chemistry
Students from the high school to the doctoral level played an integral role in the complex task of collecting and analyzing the movement of the tiny molecular motors.
"Involvement in this type of research can be an enlightening, and in some cases life changing, experience for students," said Sykes. "If we can get people interested in the sciences earlier, through projects like this, there is a greater chance we can impact the career they choose later in life."
As proof that gaining a scientific footing early can matter, one of the high school students involved in the research, Nikolai Klebanov, went on to enroll at Tufts; he is now a sophomore majoring in chemical engineering.
In addition to Sykes and Klebanov, additional authors on the paper are Heather L. Tierney, Ph.D., a managing editor at the American Chemical Society who earned her doctorate at Tufts; Colin J. Murphy and April D. Jewell, both doctoral candidates in chemistry at Tufts; Ashleigh E. Baber, Ph.D., a research fellow at Brookhaven National Laboratory who earned her doctorate at Tufts; Erin V. Iski, Ph.D., a research fellow at Argonne National Laboratory who earned her doctorate at Tufts; Harout Y. Khodaverdian, a 2011 graduate of Malden High School; and Allister F. McGuire, a chemistry major at Tufts.
This work was supported by the National Science Foundation, the Beckman Foundation and the Research Corporation for Scientific Advancement.
"Experimental demonstration of a single-molecule electric motor." Nature Nanotechnology. Published online September 4, 2011. DOI: 10.1038/NNANO.2011.142.
Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university is widely encouraged.
Katie Cinnamond | EurekAlert!
Flavins keep a handy helper in their pocket
25.04.2018 | University of Freiburg
Complete skin regeneration system of fish unraveled
24.04.2018 | Tokyo Institute of Technology
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
25.04.2018 | Physics and Astronomy
25.04.2018 | Physics and Astronomy
25.04.2018 | Information Technology