Highly Stretchable Miniature Strain Sensor for Large Dynamic Strain Measurement

In this letter, a new type of highly stretchable strain sensor was developed to measure large deformation of a specimen subjected to dynamic loading. The sensor was based on the piezoresistive response of carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite thin films. The piezoresistive response of CNT composite gives fast response in strain measurement, whereas the ultrasoft PDMS matrix provides high flexibility and ductility for large strain measurement. Experimental results showed that the CNT/PDMS sensor is capable of measuring large strains (up to 26%) with an excellent linearity and ultrafast response (less than 30 mu s). This stretchable strain sensor also exhibits much higher sensitivities, with a gauge factor of as high as 80, than the conventional foil strain gages. These strain sensing capabilities (large strain, ultafast response, high linearity, and high gauge factor) make the fabricated sensor suitable for high-rate dynamic loading test applications.