Flexible and Transparent Strain Sensors Based on Super-aligned Carbon Nanotube Films
Highly flexible and transparent strain sensors are fabricated by directly coating super-aligned carbon nanotube (SACNT) films on polydimethylsiloxane (PDMS) substrates. The fabrication process is simple, low cost, and favorable for industrial scalability. The SACNT/PDMS strain sensors present a high sensing range of 400%, fast response of less than 98 ms, and low creep of 4% at 400% strain. The SACNT/PDMS strain sensors can withstand 5,000 stretching–releasing cycles at 400% strain. Moreover, the SACNT/PDMS strain sensors are transparent with 80% transmittance at 550 nm. In situ microscopic observation clarifies that the surface morphology of the SACNT film exhibits a reversible change during the stretching and releasing processes and thus its electrical conductance is able to fully recover to the original value after the loading–unloading cycles. The SACNT/PDMS strain sensors have the advantages of wide sensing range, fast response, low creep, transparency, and excellent durability, and thus show great potential in wearable devices to monitor fast and large-scale movements without affecting the appearance of the devices.