In Roman mythology, Janus was the god of change and transition, often portrayed with two faces gazing in opposite directions. At the University of Illinois at Urbana-Champaign, Janus particles are providing insight into the movement of molecules, and serving as the basis for new materials and sensors.
"By modifying the surface of colloidal particles into a Janus chemical compound, we can measure the rotational dynamics of single colloidal particles in suspension as well as at interfaces," said Steve Granick, a professor of materials science and engineering, chemistry and physics. "We can also take advantage of the particles two very dissimilar sides to create families of microsensors."
Using a metal-deposition technique, Granick and his research team -- graduate students Liang Hong and Steven Anthony, and postdoctoral research associate Huilin Tu -- make particles half-covered by metal, and generate geometrically symmetric but chemically asymmetric materials. Trapped inside the micron-size particles are fluorescent dyes, which can only be seen through the uncoated hemisphere, not through the metal-coated hemisphere.
James E. Kloeppel | EurekAlert!
New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center
Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
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