Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Thermal Superconductivity in Carbon Nanotubes Not So “Super” When Added to Certain Materials

12.11.2003


Superb conductors of heat and infinitesimal in size, carbon nanotubes might be used to prevent overheating in next-generation computing devices or as fillers to enhance thermal conductivity of insulating materials, such as durable plastics or engine oil. But a research team at Rensselaer Polytechnic Institute has discovered that the nanotubes’ role as thermal superconductors is greatly diminished when mixed with materials such as polymers that make up plastics.



“Carbon nanotubes are superior thermal conductors by themselves. But, that doesn’t mean they will exhibit the same level of high conductivity when integrated into other materials,” says Pawel Keblinski, assistant professor of materials science and engineering and head of Rensselaer’s research team. His team’s research is published in this month’s issue of Nature Materials.

A global team of researchers was optimistic when a one-percent fraction of carbon nanotubes was added to epoxy and other organic materials, and the thermal conductivity of the newly created composites increased two- or threefold. But, using conventional engineering estimates, Keblinski noted that the composites’ conductivity should have had 50-fold increases.


Why such disparity between the experiment and the expectations?

“Atoms forming stiff carbon nanotubes vibrate at much higher frequencies than the atoms in the surrounding material. This leads to high interfacial resistance for the heat flow between the tubes and the other elements,” Keblinski says.

Energy exchange between two different elements is immediate and plentiful when frequencies in both are similar. Interfacial resistance happens when the frequencies are different, and the heat energy has a difficult time taking the leap from one element to the next.

To test the magnitude of the problem, Keblinski and his Rensselaer collaborators performed computer simulations on a model nanotube composite. Meanwhile, another research group headed by David Cahill at the University at Illinois at Urbana Champaign, heated real carbon nanotubes with a laser.

From the rate of cooling, in both the simulation and the physical experiment, the researchers derived the value of the interfacial resistance. In both instances, they found the resistance is so high that it limits the thermal conductivity of the nanotubes.

One way to reduce the interfacial resistance in such nanocomposites is to induce a stronger bond between the nanotube and other materials to make it easier for heat to cross from one element to the next. However, extensive bonding may distort the original nanotube structure that allows the tubes to be a superconductor of heat in the first place.

Still, Keblinski is optimistic about the use of carbon nanotubes to improve insulating materials. “By adding a small fraction of carbon nanotubes to such materials, we can still increase the thermal as well as electrical conductivity. So, although we may have to lower our expectations, we have not given up hope quite yet that nanotubes will improve materials for a number of applications,” Keblinski says.


About Rensselaer

Rensselaer Polytechnic Institute, founded in 1824, is the nation’s oldest technological university. The school offers degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research conducted in a wide range of research centers that are characterized by strong industry partnerships. The Institute is especially well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.

Jodi Ackerman | Rensselaer News

More articles from Materials Sciences:

nachricht Glass's off-kilter harmonies
18.01.2017 | University of Texas at Austin, Texas Advanced Computing Center

nachricht Explaining how 2-D materials break at the atomic level
18.01.2017 | Institute for Basic Science

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>