Measuring gooey materials; optical nanocrystallography; giant laser.
Measuring gooey materials
The National Institute of Standards and Technology (NIST) and Thermo Fisher Scientific have devised an instrument that correlates the flow properties of “soft gooey” materials, such as gels, molten polymers and biological fluids.
The instrument, called a rheo-Raman microscope, combines three instruments into one system. First, the system incorporates a Raman spectrometer. This technology shines a laser on the sample. It measures the portion of scattered light, revealing the vibrational energy levels of molecules in a sample.
Second, the system also includes a rotational rheometer. This technology measures how a liquid flows in response to stress. Third, it makes use of an optical microscope, which collects polarized light. This, in turn, enables measurements of a feature.
The simultaneous measurements from this system enable researchers to understand the properties of soft materials. Soft materials, which share features of liquids and solids, include plastics, liquid crystal displays, contact lenses, biopharmaceuticals and others.
The tool helps understand the flow behavior in these materials. It measures strength, hardness, or electrical conductivity. “It allows you to trace the evolution of microstructure across a range of temperatures and to do it in one controlled experiment rather than in two or three separate ones. It provides insights that would be very difficult to obtain through measurements made one at a time,” said Anthony Kotula, a NIST materials scientist.
The Department of Energy’s Lawrence Berkeley National Laboratory and the University of Colorado have developed a new form of optical nanocrystallography.
Crystallography is concerned about the structures and properties of crystals. Berkeley Lab and others have devised a technology called scattering-type scanning near-field optical microscopy or s-SNOM. The infrared technique enables imaging resolution down to about 10nm to 20nm.
More specifically, researchers combined the power of Berkeley Lab’s Advanced Light Source (ALS) and infrared light from an atomic force microscope (AFM). The ALS is a particle accelerator that generates bright beams of X-ray light.
Used in X-metrology applications, the ALS produces light in a range of infrared to X-rays. Then, researchers use an imaging technique called s-SNOM.
For this, researchers focused the infrared light onto the tip of the AFM. The tip becomes an ultrasensitive antenna. Scattered light moves over the tip. The data is recorded by a detector, which produces high-resolution images.
In this experiment, researchers used the technique to explore the crystalline features of an organic semiconductor material known as perylenetetracarboxylic dianhydride. But generally, the technology allows researchers to direct the infrared light on specific chemical bonds and their arrangement. It shows the crystal features of a sample.
“Our technique is broadly applicable,” said Hans Bechtel, an ALS scientist. “You could use this for many types of material—the only limitation is that it has to be relatively flat.”
Markus Raschke, a CU-Boulder professor, added: “The sensitivity of this technique is going from an average of millions of molecules to a few hundred, and the imaging resolution is going from the micron scale to the nanoscale.”
European XFEL, a large international research facility with eleven European member countries, is readying its 3.4-km long underground X-ray laser.
The system is the world’s largest X-ray laser. It will generate ultrashort X-ray flashes at 27,000 times per second. The system is located in the German federal states of Hamburg and Schleswig-Holstein. It comprises three large sites above ground and several underground tunnels.
Using X-ray flashes from the European XFEL, scientists can map the atomic details of viruses, decipher the molecular composition of cells, take three-dimensional images of materials, film chemical reactions and study the processes in the interior of planets
Scientists will be able to perform experiments at the facility for the first time in 2017.