Extremely Elastic Wearable Carbon Nanotube Fiber Strain Sensor for Monitoring of Human Motion

TLDR

Wearable electronics demand highly elastic strain sensors to monitor diverse physical parameters, driving next‑generation device development. The study reports an ultrahigh stretchable, wearable device made from dry‑spun CNT fibers. The device is fabricated by dry‑spinning CNT fibers onto Ecoflex, and its strain sensitivity arises from reduced conductive pathways and contact areas during stretching, while biaxially oriented arrays provide independent cross‑sensitivity for multi‑axis measurement. The device can stretch over 900% with high sensitivity, responsiveness, and durability, and it has been demonstrated as a strain gauge and multiaxial motion sensor that can be integrated into motion‑detection systems.

Abstract

The increasing demand for wearable electronic devices has made the development of highly elastic strain sensors that can monitor various physical parameters an essential factor for realizing next generation electronics. Here, we report an ultrahigh stretchable and wearable device fabricated from dry-spun carbon nanotube (CNT) fibers. Stretching the highly oriented CNT fibers grown on a flexible substrate (Ecoflex) induces a constant decrease in the conductive pathways and contact areas between nanotubes depending on the stretching distance; this enables CNT fibers to behave as highly sensitive strain sensors. Owing to its unique structure and mechanism, this device can be stretched by over 900% while retaining high sensitivity, responsiveness, and durability. Furthermore, the device with biaxially oriented CNT fiber arrays shows independent cross-sensitivity, which facilitates simultaneous measurement of strains along multiple axes. We demonstrated potential applications of the proposed device, such as strain gauge, single and multiaxial detecting motion sensors. These devices can be incorporated into various motion detecting systems where their applications are limited to their strain.