However, man's knowledge of micro- and nanoscale heat flow is rudimentary at best. Now, a research team at the University of Illinois at Urbana-Champaign (UIUC) has developed a novel system for examining and measuring nanoscale thermal conductance at the interface between two materials.
With further refinement, the scientists believe their advance may one day provide data for applications such as harvesting electricity from waste heat, better cooling of microelectronic devices and "heat-seeking" targeting of disease cells by hyperthermal (above normal body temperature) therapeutics.
The team's findings will be presented by Mark Losego, formerly a post-doctoral fellow at UIUC and now a research assistant professor in chemical and biomolecular engineering at North Carolina State University, during the AVS 59th International Symposium and Exhibition, held Oct. 28-Nov. 2, 2012, in Tampa, Fla.
At the nanoscale, thermal properties are the result of vibrations between neighboring atoms. Bonds between atoms carry these vibrations similar to an oscillating spring. The UIUC team developed a technique for studying the effects of these bonds on heat transport across an interface between two different materials. "We wanted a system where we could observe, analyze and quantify thermal flow across an interface with atomic-level precision," Losego says.
The system starts with a substrate base of quartz crystal, upon which the researchers place molecular chains that are 12 carbon atoms long. At the base of each chain is a chemical "cap" that covalently bonds to quartz. The attraction of these caps to the substrate spontaneously aligns all of the carbon chains into an ordered array of molecules known as a self-assembled monolayer (SAM). At the opposite end of each carbon chain is a different kind of cap, either a thiol (sulfur and hydrogen) group that bonds strongly to metals or a methyl group (carbon and hydrogen) that bonds weakly.
"We then make use of a viscoelastic silicone stamp to 'transfer print' gold layers onto the SAM surface," Losego explains. "This process is similar to transferring a decal onto a T-shirt where the gold film is the 'decal' attached to the silicone stamp 'backing'. When we slowly peel away the silicone, we leave the gold layer on top of the SAM."
It is at the interface between the gold film and the SAM, Losego says, where nanoscale heat flow is characterized. "Changing the chemical groups that are in contact with the gold layer allows us to see how different bonds affect heat transfer," he adds.
Combined with an ultrafast laser technique capable of monitoring temperature decay (or heat loss) with picosecond (trillionth of a second) resolution, the UIUC researchers are able to use their experimental system to evaluate heat flow at the atomic scale. "We heat the gold layer attached to the monolayer and can monitor temperature decay with time," Losego explains. "Concurrently, we observe oscillations in the gold film that indicate the strength of the bonds at the gold-SAM junction. Using these measurements we are able to independently verify that strong bonds [fast-decaying oscillations] have rapid heat transfer while weak bonds [slowly decaying oscillations] have slower heat transfer."
The researchers plan to refine their nanoscale thermal measurement system and develop theoretical calculations to better interpret the data it produces.
Main meeting website: http://www2.avs.org/symposium/AVS59/pages/greetings.html
Technical Program: http://www.avssymposium.org/
Housing and Travel Information: http://www2.avs.org/symposium/AVS59/pages/housing_travel.html
The AVS Pressroom will be located in the Tampa Convention Center. Your complimentary media badge will allow you to utilize the pressroom to write, interview, collect new product releases, review material, or just relax. The media badge will also admit you, free of charge, into the exhibit area, lectures, and technical sessions, as well as the Welcome Mixer on Monday evening and the Awards Ceremony and Reception on Wednesday night. Pressroom hours are Monday-Thursday, 8-5 p.m.
To register, please contact:Della Miller, AVS
Founded in 1953, AVS is a not-for-profit professional society that promotes communication between academia, government laboratories, and industry for the purpose of sharing research and development findings over a broad range of technologically relevant topics. Its symposia and journals provide an important forum for the dissemination of information in many areas of science and technology, enabling a critical gateway for the rapid insertion of scientific breakthroughs into manufacturing realities.
Catherine Meyers | EurekAlert!
Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters
Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Life Sciences
25.10.2016 | Earth Sciences