Researchers look at alternative materials for reducing the heat in electronic devices.
9 March
Chinese researchers have developed a coating that releases water vapour which can be used to prevent electronic devices from overheating.
Currently small electronic devices are kept cool with the use of phase-change materials such as waxes and fatty acids. When they melt, the material absorbs heat produced by the device. However, the total amount of energy exchanged during this solid-liquid transition in relatively low.
A team from Shanghai Jiao Tong University have been working with metal organic frameworks (MOFs), a group of porous materials that can absorb moisture from the air and release water vapour when heated. MOFs can hold a large amount of water, allowing them to take away more heat when temperatures rise.
The team used a MOF called MIL-101(Cr) to coat three 16cm2 aluminium sheets of different thicknesses and heated them on a hotplate. The coating delayed the temperature rise of the sheets. An uncoated sheet reached 60oC after 5.2 minutes. The sheet with the thinnest coating took 11.7 minutes to reach the same temperature. Once the heat source is removed the MOF can quickly recover by absorbing moisture.
However, it is argued that silica or some zeolites, which are cheaper, could do the same job and the use of MOFs may not be appropriate for cooling chips in data devices.
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