Wearable strain sensor made of carbonized cotton cloth

An economical strain sensor is fabricated by sandwiching a carbonized cotton cloth (CC) between two polydimethylsilane (PDMS) films. The natural networks of carbon fibers in CC bring the sensor changeable resistance under strain. This sensor is used to monitor three types of strains, which are pressure, bending and torsion, while the resistance response of which shows exponential relation to strains. Response time of the sensor is less than 35 ms. The maximum resistance decrease of the CC sensor under pressure, bending and torsion are 27, 65 and 45% respectively. The gauge factors at 3% strain of the sensor under bending and torsion are 15 and 8 respectively. The sensor is compressed under pressure, and is stretched under bending or torsion. The sensor shows higher sensitivity under tension compared to that under compression. The high sensitivity, great flexibility and stability, easy fabricating make the CC sensor a promising candidate in wearable sensing devices.