American engineers have learned how to create clothes with dozens of embedded sensors of temperature and motion. Strip sensors are located between the layers of fabric and invisible to others, and they collect a small device tacked on the buttons-fasteners that simultaneously act as electrodes. After releasing the device the clothes can be washed in the washing machine and its properties practically does not suffer, say the authors of the article in npj Flexible Electronics.
Researchers for many years refuse to offer a separate wearable device and go to smart clothing with integrated electronics. Some such developments already exist, and even sold, but mostly they all have one common fundamental problem — difficult to make functional clothes that would withstand the constant strong stretching and it does not hamper the movements of the person. Most often this problem is solved either by using a new, but expensive and not applicable for mass production of materials, or the fact that the electronics are inserted only in a small part of a garment, for example, in the sleeve.
Engineers from the Massachusetts Institute of technology, headed Dagdeviren Canan (Canan Dagdeviren) chose a more practical approach. The basis they took the polyester fabric from which they knitted sweater with horizontal channels — double-layered tissue. In these channels are inserted flexible strip with electronics. They consist of copper conductive paths in the form similar to a sine wave — this allows the track to withstand severe tensile (tens of percent).
In some areas strips installed Playground with chip for measurement (thermometer or accelerometer). In the appropriate places on the inside of the sweater in the channels made the cut outs to the sensors snugly to the body. Strip sensors are insulated using a polymer film, so they can work in water and under tension. Strength tests showed that the strips can withstand thousands of cycles of stretching 30 percent without significant degradation of conductive properties. In addition, the authors checked the washing fastness: the resistance is not changed after 10 cycles of the washing machine, and during one of the cycles, three temperature sensor and accelerometer successfully continuously collected data.