While there are already clothing materials that help keep wearers cool simply by allowing heat to escape, an experimental new fabric coating goes a step further. Utilizing a whole bunch of nanodiamonds, it actually draws heat away from the body.
First of all, unlike their non-nano counterparts, nanodiamonds are not expensive.
They're nanoscale diamond particles that can be cheaply and easily manufactured, and which have the same "carbon lattice" internal structure as regular diamonds. Among other things, that structure gives them excellent thermal conductivity – in other words, they're very good at conducting heat.
Led by doctors Shadi Houshyar and Aisha Rehman, a team of scientists at Australia's RMIT University recently mixed nanodiamond powder with polyurethane and solvent. The resulting solution was then applied to one side of a sheet of ordinary cotton via an electrospinning technique.
After being left to cure, the solution formed a coating which consisted of a web of nanofibers bonded to the larger cotton fibers. If the fabric were to be used in clothing, the coated side would face in towards the wearer's skin. The exterior surface was left uncoated, to keep it from drawing in ambient heat.
Samples of the material were placed with their uncoated sides facing towards a nearby 100 ºC (212 ºF) hotplate for 10 minutes, then removed from the area and left to cool for another 10 minutes. It was found that as compared to control samples of untreated cotton, the treated samples released 2 to 3 ºC (3.6 to 5.4 ºF) more heat through their coated side within the cooling period.
The treated cotton was also found to offer better protection from ultraviolet light. That said, its air permeability and moisture absorption weren't quite as good as those of untreated cotton, but still remained within an acceptable range.
"While two or three degrees may not seem like much of a change, it does make a difference in comfort and health impacts over extended periods and in practical terms, could be the difference between keeping your air conditioner off or turning it on," said Houshyar. "There’s also potential to explore how nanodiamonds can be used to protect buildings from overheating, which can lead to environmental benefits."
A paper on the research was recently published in the journal Polymers for Advanced Technologies.
Source: RMIT University
