Group of Japanese researchers at AIST have successfully developed a strain sensor with oriented single-walled carbon nanotubes (single-walled CNT) films. The sensor films are bonded to a stretchable polymer substrate which can measure strains by detecting changes in the electrical resistance of the films. The CNT stain sensor is capable of detecting of up to 280%, around 50 times of what can be detected by conventional metal strain sensors. Furthermore, its added durability has been up to test with 10,000 repeated applications of strain less than 150% while having a strain response time of only 14 ms, shortest among the sensors that can measure large strain s of more than 100%. In addition of this, the sensor is less susceptible to creep than strain sensors that are made of a composite of an electrically conductive material and a polymer while being 20 times faster in creep recovery. The CNT strain sensor can easily be attached to clothing or the body for monitoring such movement as knee bending and straightening, finger movement, breathing as well as voice production. The new sensors are expected to be used in a future wearable devices, as well as recreational and medical applications.
