Non-wetting fabric is able to 'drain' perspiration
21 May 2013
A new application for microfluidics: hydrophilic threads stitched into a highly water-repellent fabric act as 'drains' for perspiration.
Stitched water channels draw fluid away from the skin and channel it to a collection point
Developed by bioengineers at the University of California, Davis, the new fabric works like human skin, forming excess sweat into droplets that drain away by themselves.
One area of research in Professor Tingrui Pan's Micro-Nano Innovations Laboratory at UC Davis 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 medical diagnostic systems.
Graduate students threads stitched into a highly water-repellent 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 micro-fabrication techniques so it is compatible with the textile manufacturing process and very easy to scale up," said Xing, lead graduate student on the project.
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 water-pumping effect keeps working even when the water-conducting fibres are completely saturated, because of the sustaining pressure gradient generated by the surface tension of droplets.
The rest of the fabric stays completely dry and breathable. By adjusting the pattern of water-conducting fibers and how they are stitched on each side of the fabric, the researchers can control where perspiration is collected and where it drains away on the outside.