It is now possible to spray motion-sensing technology onto store-bought garments, meaning any item of clothing could become a wearable sensor.
鈥淭he main goal of our work is to incorporate sensing materials into fabrics, any kind of fabrics 鈥� you know, commercial garments like a sock or a glove, or anything else that is available out there,鈥� says at Purdue University in Indiana. He and his colleagues developed a way to do so by spraying a conductive compound on a variety of fabrics.
Their spraying device has two chambers, each of which is filled with a different compound. These compounds mix and chemically react to form a polymer only during spraying. The solid, stretchy and electrically conductive polymer that forms in this reaction then hits the fabric and becomes the most important part of a strain sensor. The researchers could lay down the polymer in any pattern with sub-millimetre precision.
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When they stretched the fabric, the polymer motif 鈥� a wavy line or a spiral, for instance 鈥� stretched with it and this changed its electrical resistance. So, the researchers could print a pattern on a glove or a knee brace and then detect joint motion 鈥� which stretches the garment 鈥� by running a small current through the polymer and monitoring the changes in its electrical resistance.
The team found that this method worked on common fabrics like cotton, wool and Lycra. After adding a commercial fabric sealant on top of the polymer, it continued to work as a sensor even when the sprayed-on garments were laundered 30 times.
at the University of Auckland in New Zealand says that polymer-based, spray-on methods could be used in physical therapy or other medical settings, where adding a sensor to a garment that already fits a patient would be more practical than using stiffer and bulkier devices with hard components and wires. However, expanding the printing process so that many garments and patterns can be sprayed simultaneously may be technologically challenging, he says.
Lee says the researchers want to devise more polymers with slightly different compounds so that they can sense not just strain but also properties like pressure, temperature or chemicals present in sweat.
ACS Nano
