Heat Transfer Under ExaminationCategory: Science & Technology
Posted: October 31, 2012 09:22AM
At the macroscale, man understands things pretty well, thanks largely to the fact that we exist on that scale. At the micro- and nanoscale though, our understanding fades away, especially with regard to heat. Light and electricity we understand fairly well, but our understanding of heat transfer is quite lacking, but researchers at the University of Illinois at Urbana-Champaign are working to change that, as reported by the American Institute of Physics.
As photons carry light and electrons carry electricity, we know that phonons carry heat, but exactly how those packets of vibrational energy move from particle to particle is difficult to observe. The researchers accomplished this by using a self-assembled monolayer (SAM) of carbon chains. On one end of the chains were caps that attached to the silicon substrate, while at the other end were one of two caps that connect to a layer of gold. The strength of the bond between the gold and the SAM was dependent on the cap, and that variability is what the researchers used to study heat transfer. Using a laser the researchers were able to analyze the loss of heat in the system at the atomic scale with picosecond resolution.
Thus far they have confirmed that stronger bonds transfer heat more quickly than weaker bonds. With more observations though, they hope to construct theories to explain the data they will be collecting.