Ultra-stretchable and highly sensitive strain sensor based on gradient structure carbon nanotubes

Abstract

High stretchability and sensitivity of strain sensors are two properties that are very difficult to combine together into one material, due to the intrinsic dilemma of the opposite requirements of robustness of the conductive network. Therefore, the improvement of one property is always achieved at the expense of decreasing the other property, and preventing its practical application. Inspired by the micro-structure of the copolymer, which consists of stretchable amorphous and strong crystal domains, we developed a highly stretchable and sensitive strain sensor, based on innovative gradient carbon nanotubes (CNTs). By integrating randomly oriented and well aligned CNTs, acting as sensitive and stretchable conductive elements, respectively, into a continuous changing structure, our strain sensors successfully combine both a high sensitivity (gauge factor (GF) = 13.5) and ultra-stretchability (>550%). With a fast response speed (<33 ms) and recovery speed (<60 ms), lossless detection of a 8 Hz mechanical signal has been easily realized. In addition, the gradient CNTs strain sensors also showed great durability in a dynamic test of 12 000 cycles, as well as extraordinary linearity and ultra-low working voltage (10 mV). These outstanding features mean our sensors have enormous potential for applications in health monitoring, sports performance monitoring and soft robotics.

Flexible Sandwich Structural Strain Sensor Based on Silver Nanowires Decorated with Self‐Healing Substrate

“…The responses of the sandwich‐structured strain sensor to the dynamic loading profile and hysteresis curve are shown in Figure and Figure S5, Supporting Information, respectively. The response of sandwich‐structured strain sensor for the stretch/release cycles is in good agreement with the loading profile, there is no obvious drifting and hysteresis in the response of the strain sensors even for ε larger than 40% of the stretch/release cycles, indicating a better performance compared with CNT based strain sensors just ε = 20% . Even the sandwich‐structured strain sensor with a larger strain (e.g., ε = 60%) shows a smaller hysteresis in the response compared with the sandwiched structured strain sensors of just AgNWs‐PDMS nanocomposites in the reference …”

Direct Patterning of Carbon Nanotube via Stamp Contact Printing Process for Stretchable and Sensitive Sensing Devices

“…S6. The similar sensing mechanism of nanowires-and nanotubes-based strain sensor has been reported in our previous work [41] and several papers [26,42,43] published by other groups. Furthermore, the thickness of the transferred CNT plays a very important role in the sensitivity of the strain sensor.…”

“…Under applied strain, the distance between the adjacent CNTs will increase, and some of the CNTs will rotate to the axis of stretching and form conductive CNT bridges. As reported in our early work [41], the CNTs are still connected to each other by the CNT bridges, even the strain arrived 270%. Therefore, the sensitivity of the strain sensor with aligned CNT is much smaller than the one with random CNT, as shown in Fig.…”

Learning from an Intelligent Mechanosensing System of Plants

“…The mechanosensor has a huge range of strain up to 760% (sensitivity 9.2%) compared with only 70% for the “straight” design. This helical strain sensor is highly comparable to other ultrastretchable strain sensors . There was no observable signal degradation after 1000 testing cycles and excellent sensing signal reproducibility fast response times of ≈100 ms.…”