Multiscale nanowire-microfluidic hybrid strain sensors with high sensitivity and stretchability

Songjia Han,Xuchun Gui,Hui-Jiuan Chen,Chunrui Liu,Chuan Liu,Sheng Chu,Huihua Xu,Dongyuan Yao,Huanliang Zheng,Kanghong Yan

doi:10.1038/s41528-018-0029-x

Abstract

Nanomaterials with low-dimensional morphology have been explored for enhancing the performance of strain sensors, but it remains difficult to achieve high stretchability and sensitivity simultaneously. In this work, a composite structure strain sensor based on nanomaterials and conductive liquid is designed, demonstrated, and engineered. The nanowire-microfluidic hybrid (NMH) strain sensor responds to multiscale strains from 4% to over 400%, with a high sensitivity and durability under small strain. Metal nanowires and carbon nanotubes are used to fabricate the NMH strain sensors, which simultaneously exhibit record-high average gauge factors and stretchability, far better than the conventional nanowire devices. Quantitative modeling of the electrical characteristics reveals that the effective conductivity percolation through the hybrid structures is the key to achieving high gauge factors for multiscale sensing. The sensors can operate at low voltages and are capable of responding to various mechanical deformations. When fixed on human skin, the sensors can monitor large-scale deformations (skeleton motion) and small-scale deformations (facial expressions and pulses). The sensors are also employed in multichannel, interactive electronic system for wireless control of robotics. Such demonstrations indicate the potential of the sensors as wearable detectors for human motion or as bionic ligaments in soft robotics.

Highlights

In recent years, strain sensors have shown potential for soft electronics applications because they can be used for human body motion detection, human health monitoring systems, and man–machine interactions.[1,2] In addition, strain sensors can be useful for building artificial body parts for humans, soft robotics, and bionic robotics in the future.[3]
The present study offers a new type of sensor that will be especially useful for multiscale sensing and potentially suitable for artificial joints or sensing units in soft robotics
We proposed and fabricated nanowire-microfluidic hybrid (NMH) strain sensors that could be suitable for multiscale sensing

Summary

INTRODUCTION

Strain sensors have shown potential for soft electronics applications because they can be used for human body motion detection, human health monitoring systems, and man–machine interactions.[1,2] In addition, strain sensors can be useful for building artificial body parts for humans, soft robotics, and bionic robotics in the future.[3]. E Comparisons of the average GFs against the maximum stretchability for previously reported strain sensors the CuNW film is far lower than the resistance of the PEDOT:PSS solution, the primary resistance of the hybrid structural strain sensor is mainly dominated by the property of the nanowire film These strain sensors were tested under strains, and the electrical responses were characterized by the variations in the relative resistances, ΔR/R0 = (R–R0)/R0, where R0 and R correspond to the original resistance and the real-time resistance under stretching, respectively. C, f Corresponding schematic diagrams of stretched nanowire or nanotube networks (upper) and stretched devices (lower), showing the resistance networks These schemes illustrate the conducting mechanisms of the NMH strain sensors corresponding to the evolution of the morphology on the left. SFÁE, where ε is the applied strain, F is tension, E is Young’s modulus of the substrate, and S is

CONCLUSION

Findings

EXPERIMENTAL METHODS