Flexible and Anisotropic Strain Sensors Based on Highly Aligned Carbon Fiber Membrane for Exercise Monitoring

Abstract

AbstractFlexible strain sensors have promising applications in deformation detection and have attracted tremendous attention. However, it is still a challenge to detect multidirectional strains and further enhance the sensing performance including high sensitivity and durability. Herein, successfully prepared aligned graphene oxide/polyacrylonitrile composite fiber membrane by optimized microfluidic spinning process is presented, and highly aligned carbon fiber membrane (CFM) by stabilization and carbonization is obtained. The flexible strain sensors are fabricated based on the CFM with different fiber arrangement directions, exhibiting good sensing performance and remarkable anisotropic electromechanical behaviors. When the fiber arrangement is parallel to the direction of stress application, the gauge factors (GFs) of the sensor are 399 in the strain range of 0‐12%, and 10 688 of 12‐15% strain. When the fiber arrangement is perpendicular to the stress direction, the GFs of the sensor are 49.8 and 830.7 under the strain of 0‐45% and 45‐50%, respectively. Meanwhile, the flexible and anisotropic strain sensors are endowed with excellent linearity, dynamic stability under different stretching rates and strain levels, rapid response time (< 300 ms), and good durability (over 1000 cycles). Remarkably, it has been demonstrated the anisotropic strain sensors could be applied in detecting human activity and assisting badminton training.