WASHINGTON (TIP): Bioengineers at the University of California, Davis, have invented a waterproof fabric that whisks away sweat using microfluidic technology. The new fabric works like human skin, forming excess sweat into droplets that drain away by themselves, said Tingrui Pan, professor of biomedical engineering at the university.

One area of research in Pan’s Micro-Nano Innovations Laboratory is a field known as microfluidics, which focuses on making ‘lab on a chip’ devices that use tiny channels to manipulate fluids. Pan and his colleagues are developing such systems for applications like medical diagnostic tests. Graduate students Siyuan Xing and Jia Jiang developed a new textile microfluidic platform using hydrophilic (water-attracting) threads stitched into a highly waterrepellent fabric.

They were able to create patterns of threads that suck droplets of water from one side of the fabric, propel them along the threads and expel them from the other side. “We intentionally did not use any fancy microfabrication techniques so it is compatible with the textile manufacturing process and very easy to scale up,” said Xing. It’s not just that the threads conduct water through capillary action.

The water-repellent properties of the surrounding fabric also help drive water down the channels. Unlike conventional fabrics, the waterpumping effect keeps working even when the water-conducting fibres are completely saturated, because of the pressure generated by the surface tension of droplets. The rest of the fabric stays completely dry. By adjusting the pattern of water-conducting fibres and how they are stitched on each side of the fabric, the researchers control where sweat is collected and where it drains away on the outside. The innovation is good news for workout enthusiasts, athletes and clothing manufacturers.