Super-stretchable, Transparent Carbon Nanotube-Based Capacitive Strain Sensors for Human Motion Detection

TLDR

Advanced bio‑interactive electronics require mechanically compliant sensors capable of detecting extremely large strain. The authors aim to create CNT‑based capacitive strain sensors that can detect strains up to 300 %. They design multifunctional sensors that retain durability after thousands of cycles. The CNT strain gauges exhibit deterministic, linear capacitive response with a gauge factor near 1, ultrafast sub‑second dynamics, no overshoot or relaxation, and high sensitivity, enabling applications such as a data glove and respiration monitor.

Abstract

Realization of advanced bio-interactive electronic devices requires mechanically compliant sensors with the ability to detect extremely large strain. Here, we design a new multifunctional carbon nanotube (CNT) based capacitive strain sensors which can detect strains up to 300% with excellent durability even after thousands of cycles. The CNT-based strain gauge devices exhibit deterministic and linear capacitive response throughout the whole strain range with a gauge factor very close to the predicted value (strictly 1), representing the highest sensitivity value. The strain tests reveal the presented strain gauge with excellent dynamic sensing ability without overshoot or relaxation, and ultrafast response at sub-second scale. Coupling these superior sensing capabilities to the high transparency, physical robustness and flexibility, we believe the designed stretchable multifunctional CNT-based strain gauge may have various potential applications in human friendly and wearable smart electronics, subsequently demonstrated by our prototypical data glove and respiration monitor.