Scientists studying the behavior of platinum particles immersed in hydrogen peroxide may have discovered a new way to propel microscopic machines. The new mechanism is described in The Journal of Chemical Physics, which is produced by AIP Publishing.
This image shows a possible application of chemical micromotors.
Credit: Daigo Yamamoto/Doshisha
Micro-sized machines operate under very different conditions than their macro-sized counterparts. The high surface-area-to-mass ratio of tiny motors means they require a constant driving force to keep them going. In the past, researchers have relied on asymmetric chemical reactions on the surface of the motors to supply the force.
For example, Janus motors, are spherical particles coated with a different material on each side. One of the sides is typically made of a catalyst like platinum, which speeds up the reaction that converts hydrogen peroxide into water and oxygen. When the Janus motor is immersed in hydrogen peroxide, oxygen bubbles form more quickly on the platinum side, pushing the sphere forward.
Researchers from Doshisha University in Kyoto, Japan have now discovered, however, that two-sided materials aren't necessary to make micromotors move. The researchers placed tiny spheres made only of platinum in hydrogen peroxide and observed the particles' movement through a microscope. Although the individual spheres bounced about randomly, the researchers noticed that clumps of particles began to exhibit regular motions.
The clumps shaped like teardrops moved forward, those that resembled windmills started to spin, and the boomerang shaped clumps traveled in a circle. After creating a theoretical model of the forces at work, the researchers realized they could explain the regular motions by the asymmetrical drag generated by the different shapes.
The researchers envision combining their new type of motors with existing motors to create easily controllable machines with a versatile range of motions.
Micro- and nano-sized machines may one day ferry drugs around the body or help control chemical reactions, but the Japanese team also sees a more fundamental reason to study such tiny systems.
"Micromotors may be used not only as a power source for micromachines and microfactories, but may also give us significant insight regarding mysterious living phenomenon," said Daigo Yamamoto, a researcher in the Molecular Chemical Engineering Laboratory at Doshisha University and an author on the paper that describes the new motors.
The article, " Catalytic micromotor generating self-propelled regular motion through random fluctuation" by Daigo Yamamoto, Atsushi Mukai, Naoaki Okita, Kenichi Yoshikawa and Akihisa Shioi appears in The Journal of Chemical Physics. See: http://dx.doi.org/10.1063/1.4813791
ABOUT THE JOURNAL
The Journal of Chemical Physics publishes concise and definitive reports of significant research in the methods and applications of chemical physics. See: http://jcp.aip.org
Jason Socrates Bardi | EurekAlert!
NASA's James Webb Space Telescope completes final cryogenic testing
21.11.2017 | NASA/Goddard Space Flight Center
Previous evidence of water on mars now identified as grainflows
21.11.2017 | US Geological Survey
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences