Chemically engineered sand cools electronic devices

Posted Jul 17, 2016 by Tim Sandle
Heat is a problem for many electronic devices. Overheating leads to breakdowns; and the loss of heat is not energy efficient. In order to cool down devices, and improve efficiency, technologists have been looking at a special type of sand.
Lab-on-a-chip (LOC) technology combines one to several diagnostic tests on one chip  millimeters to ...
Lab-on-a-chip (LOC) technology combines one to several diagnostic tests on one chip, millimeters to centimeters in size, that works with extremely small fluid samples.
Maggie Bartlett, NHGRI/Wikimedia Commons
The sand is not the standard sand found on beaches (formed from the remains of sea creatures), but laboratory created silicon dioxide nanoparticles coated with a high dielectric constant polymer. These nanoparticles can be made cheaply and consistently.
According to Dr. Baratunde Cola, of Georgia State University (U.S.), the sand-based nanoparticles can be added to electronic devices, like computers, in order to cool them down. With this, technology site (@HEXUSNET) tweeted: "Scientists eye potential of 'sand' for cooling powerful electronics: Its silicon dioxide with a nanoscale coat..." Similar excited tweets were sent by Newsport247 (@newsport247n) and Maria M. Surrett (@mariasurrett.)
The sand particles work due to their surface properties, which is enhanced by the silicon dioxide being coated. The coating creates a nanoscale electromagnetic effect and it is enhanced by millions of particles working together. The particles act to dissipate the heat.
Speaking with Controlled Environments magazine, Dr. Cola explains further you “can turn the nanoparticle bed into a conductor. Using the collective surface electromagnetic effect of the nanoparticles, the thermal conductivity can increase 20-fold, allowing it to dissipate heat."
The science basis relates to particles called surface phonon polaritons. These act to increase the thermal conduction in certain nanomaterials. The polaritons are quasiparticles, generated by the strong coupling of electromagnetic waves within an electric or magnetic dipole-carrying excitation. Essentially, a polariton is the result of the mixing of a photon (the elementary particle that is the basis of light) with an excitation of a material. This is a complex process, but it is essentially about creating particles with special properties through the use of electromagnetic waves to vibrate atoms.
Unlike other work using nanoparticles, the polaritons do not need light to be shined on them for the particles to activate. Instead the heat from the electronic device causes the activation.
In trials, an electronic device packed with ethylene glycol-coated nanoparticles in the air space and effective heat dissipation was measured. Further research is on-going to look at long term efficiency.
The research into the sand-cooling effect is published in the journal Materials Horizons. The paper is titled “High thermal conductivity in polaritonic SiO2 nanoparticle beds.”