In an effort to develop a material that can maintain a cool temperature in a hot environment without a power source, scientists at MIT studied camels. Specifically, they studied the fact that camels with their thick fur, are able to keep a consistent temperature while in the extremely hot climate of the desert.
A camel’s fur reduces loss of moisture from their sweat, but allows enough moisture to evaporate creating a cooling effect. Studies revealed that a camel that has been shaved loses 50% more moisture than one with its fur intact. This was the model they wanted to imitate.
The researchers developed a system that mimics camels and achieves similar results. It is made up of two layers; the bottom layer consists of a hydrogel and is meant to work similar to the sweat glands. Water evaporates easily from this layer. The upper layer is made of an aerogel which works the same way as the camel’s fur. It keeps out the hot air but allows the evaporated water to pass through.
What is a hydrogel
Hydrogels are crosslinked polymers that can absorb large amounts of water. They do not dissolve in water but maintain their structure. Many hydrogels are synthetic, but some are derived from nature.
What is an aerogel?
An aerogel is a synthetic, solid yet porous material derived from a gel. The liquid component of the gel is removed and replaced with a gas. Also like the hydrogel, it retains its structure. Aerogels are extremely light and low in density, and they have excellent thermal insulating properties.
The new material made up of two layers is no more than 1/2” thick. In the experiment, it took 200 hours for the material to lose all of its moisture compared to 40 hours when using only the hydrogel layer. The system can provide cooling five times longer than the hydrogel alone. And no electrical power source was used, only heat.
This new material could be used to preserve food freshness and medicine safety while transporting them to out of the way locations. More work needs to be done to develop a less expensive way to produce the layers, making the system able to be scaled up and feasible for wider use.
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