Mobile phones in future could sweat to keep cool: report

Scientists in China have found an inventive solution to cool a phone down when it gets really hot.

Inspired by many mammals, including humans, perspiring liquid to regulate body temperature, scientists have created a metal-based coating just three times the thickness of a human hair, which keeps the running temperature of electronics down by releasing water, according to a report.

As this turns to gas and evaporates, it takes with it the excess heat produced by the electronics.

Scientists who developed the innovative method say it is currently too expensive for widespread use but shows promise for future application.

It could be applied to all technology, including handheld electronic devices such as tablets and phones, and help avoid overheating.

”The development of microelectronics puts great demands on efficient thermal management techniques, because all the components are tightly packed and chips can get really hot,” senior author Ruzhu Wang, who studies refrigeration engineering at Shanghai Jiao Tong University said.

“For example, without an effective cooling system, our phones could have a system breakdown and burn our hands if we run them for a long time or load a big application.”

Current methods to keep electronics cool include using fans or phase change materials (PCMs), such as waxes and fatty acids, that melt when the heat increases — soaking up the excess thermal energy.

In a study published in the journal Joule, the authors publish their results which used less than 0.3 grams of material and achieved ‘significant’ results.

They coated three 16-square-centimetre aluminium sheets with a metal-based coating designed to sweat.

Called MIL-101(Cr), it was applied to three chips, each with different thicknesses —198, 313 and 516 micrometers — and heated them on a hot plate.

The average width of a human hair is 75micrometres.

An uncoated sheet reached 60°C after 5.2 minutes, where as a chip with the thinnest coating took twice this amount of time and didn’t reach 60°C until 11.7 minutes had elapsed.

The sheet with the thickest coating reached the 60°C mark after 19.35 minutes of heating.

“In addition to effective cooling, MIL-101(Cr) can quickly recover by absorbing moisture again once the heat source is removed, just like how mammals rehydrate and ready to sweat again,” Wang says.

“So, this method is really suitable for devices that aren’t running all the time, like phones, charging batteries and telecommunications base stations, which can get overloaded sometimes.”

To investigate the cooling effect of MIL-101(Cr) on actual devices, the researchers lathered their sweaty material on a computer chip. Compared to an uncoated chip, the coated one reduced the chip temperature by up to 7°C when the device was run at heavy workloads for 15 minutes.