Electronics are not very good at handling heat which is why most appliances such as refrigerators and laptops use fans to cool them down. However, what if electronics could release sweat like humans to help them cool off? Picturing your laptop release sweat as you use it at your office may seem absurd but it might be the most effective way to cool electronics in the future.
Researchers at Cornell University have taken inspiration from perspiration and developed a soft robotic gripper that automatically starts sweating when the temperature rises above a specific value. These grippers consist of a hollow finger shaped tube with pores attached to the main body made from the polymer called PNIPA; this polymer shrinks when the temperature hits about 40 degree Celsius, making it an ideal material for the robots.
The outward-facing side is made using a chemical called acrylamide that expands at high temperatures and has a rough texture that is designed to encourage evaporation off the surface. A hydraulic system is used to pump water into the main tube which is usually made from a material called Hydrogel. As the soft-robot heats up, the volume of the fingers shrink, the tiny pores, a fifth of a millimeter wide expand which squeezes the liquid contents out.
Theoretically, this was already proven effective by Thomas Wallin, at the time a candidate for a Ph.D at Cornell University. He explained that elite marathon runners lose almost four liters of sweat in an hour which corresponds to roughly 2.5 Kilowatts of cooling capacity. In comparison, a home refrigerator consumes about one kilowatt of energy over an hour. This was an incredibly significant study as it illustrated the potential of these soft robots.
But to further test his sweating soft robots, Wallin and his colleagues designed another gripper robot except this one used a mechanical fan to cool off compared to the sweating mechanism of its soft robot counterpart. An experiment was conducted in which both robots picked up hot objects while a fan blew air over them and it was found that the sweating gripper managed to drop its temperature six times faster than the non-sweating gripper. The sweating gripper cooled itself at a rate of 107 watts per kilogram of weight which is three times faster than the temperature-regulating efficiency of animals.
There are still certain limitations to this technology such as the decrease in efficiency of gripping items as the Hydrogel is released; however, this is still a research in progress which will improve over time as new mechanisms and materials are discovered. Soft robots have a wide variety of applications and these grippers could be revolutionary if used in the biomedical field to assist with surgeries.