A spirally layered carbon nanotube-graphene/polyurethane composite yarn for highly sensitive and stretchable strain sensor

This paper reports a highly sensitive and stretchable strain sensor based on a spirally layered composite yarn and the synergistic effect of carbon nanotube (CNT) and reduced graphene oxide (RGO). It is demonstrated that the addition of small amount of 2D RGO into 1D CNT network could significantly improve the strength, conductivity, and sensitivity (with gauge factor up to 2160.4) of sensor because of the formation of more connection points, while the spirally layered structure endows the sensor with large working strain of 620% and good durability owing to the protection of conducive layer by elastic substrate during stretching. These features make it promising for detection of a wide range of human activities from tiny motion of pronunciation to large movement of knee bending. Furthermore, this yarn shaped sensor can also be sewed into common textile to develop wearable electronic devices as demonstrated in this study of smart glove.